Amido spirocyclic amide and sulfonamide derivatives

ABSTRACT

Provided are amido spirocyclic amide and sulfonamide compounds, pharmaceutical compositions comprising such compounds, and methods of treatment using such compounds.

FIELD OF THE INVENTION

The present invention relates to certain amido spirocyclic amide and sulfonamide compounds, pharmaceutical compositions comprising such compounds, and methods of treating cancer, including leukemias and solid tumors, inflammatory diseases, osteoporosis, atherosclerosis, irritable bowel syndrome, and other diseases and medical conditions, with such compounds and pharmaceutical compositions. The present invention also relates to certain amido spirocyclic amide and sulfonamide compounds for use in inhibiting nicotinamide phosphoribosyltransferase (“NAMPT”).

BACKGROUND OF THE INVENTION

Nicotinamide adenine dinucleotide (NAD) plays a fundamental role in both cellular energy metabolism and cellular signaling NAD plays an important role in energy metabolism, as the pyridine ring in the NAD molecule readily accepts and donates electrons in hydride transfer reactions catalyzed by numerous dehydrogenases. The enzyme nicotinamide phosphoribosyltransferase (NAMPT, NMPRT, NMPRTase, or NAmPRTase, International nomenclature: E.C. 2.4.2.12), promotes the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to generate nicotinamide mononucleotide, which is a precursor in the biosynthesis of NAD.

NAMPT is implicated in a variety of functions, including the promotion of vascular smooth muscle cell maturation, inhibition of neutrophil apoptosis, activation of insulin receptors, development of T and B lymphocytes, and reduction of blood glucose. Thus, small molecule NAMPT inhibitors have potential uses as therapies in a variety of diseases or conditions, including cancers involving solid and liquid tumors, non-small cell lung cancer, leukemia, lymphoma, ovarian cancer, glioma, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, rhino-gastric tumors, colorectal cancer, CNS cancer, bladder cancer, pancreatic cancer and Hodgkin's disease. NAMPT inhibitors also have potential uses as therapies for diseases or conditions such as cancer, rheumatoid arthritis, diabetes, atherosclerosis, sepsis, or aging.

Rongvaux et al. have demonstrated that NAMPT is implicated in the regulation of cell viability during genotoxic or oxidative stress, and NAMPT inhibitors may therefore be useful as treatments for inflammation. Rongvaux, A., et al. J. Immunol. 2008, 181, 4685-4695. NAMPT may also have effects on the reaction of endothelial cells to high glucose levels, oxidative stress, and aging. Thus, NAMPT inhibitors may enable proliferating endothelial cells to resist the oxidative stress of aging and of high glucose, and to productively use excess glucose to support replicative longevity and angiogenic activity.

In particular, NAMPT inhibitors have been shown to interfere with NAD biosynthesis and to induce apoptotic cell death without any DNA damaging effects or primary effects on cellular energy metabolism, and thus have important anti-tumor effects. For example, the NAMPT inhibitor FK866 has these biochemical effects, and has also been shown to reduce NAD levels, induce a delay in tumor growth and enhance tumor radiosensitivity in a mouse mammary carcinoma model. See, e.g., Hasmann M. and I. Schemainda, “FK866, a Highly Specific Noncompetitive Inhibitor of Nicotinamide Phosphoribosyltransferase, Represents a Novel Mechanism for Induction of Tumor Cell Apoptosis,” Cancer Res. 2003, 63, 7436-7442; Drevs, J. et al., “Antiangiogenic potency of FK866/K22.175, a new inhibitor of intracellular NAD biosynthesis, in murine renal cell carcinoma,” Anticancer Res. 2003, 23, 4853-4858.

More recently, another NAMPT inhibitor, CHS-828, has been shown to potently inhibit cell growth in a broad range of tumor cell lines. See Olesen, U. H. et al., “Anticancer agent CHS-828 inhibits cellular synthesis of NAD,” Biochem. Biophys. Res. Commun. 2008, 367, 799-804; Ravaud, A. et al., “Phase I study and guanidine kinetics of CHS-828, a guanidine-containing compound, administered orally as a single dose every 3 weeks in solid tumors: an ECSG/EORTC study,” Eur. J. Cancer 2005, 41, 702-707. Both FK866 and CHS-828 are currently in clinical trials as cancer treatments.

There remains a need for potent NAMPT inhibitors with desirable pharmaceutical properties. Certain amido spirocyclic amide and sulfonamide derivatives have been found in the context of this invention to have NAMPT-modulating activity.

SUMMARY OF THE INVENTION

In one aspect, the invention is directed to compounds of Formula I:

wherein:

-   R is (a) an 8-, 9-, or 10-membered bicyclic heteroaryl comprising     one heteroatom selected from N, S, and O, and one, two, or three     additional N atoms, wherein said bicyclic heteroaryl is     unsubstituted or is substituted with one or more substituents     selected from the group consisting of deuterium, amino, alkylamino,     dialkylamino, alkyl, halo, cyano, haloalkyl, hydroxy, hydroxyalkyl,     and alkoxy, and wherein one or more N atoms of said bicyclic     heteroaryl is optionally an N-oxide; or     -   (b) a five- or six-membered nitrogen-linked heterocycloalkyl         ring fused to a phenyl or monocyclic five- or six-membered         heteroaryl, wherein said phenyl or heteroaryl is unsubstituted         or is substituted with one or more substituents selected from         the group consisting of deuterium, amino, alkylamino,         dialkylamino, alkyl, halo, cyano, haloalkyl, hydroxy,         hydroxyalkyl, and alkoxy; and -   R¹ is H, —(C₁₋₄alkylene)₀₋₁C(O)R^(a), —(C₁₋₄alkylene)₀₋₁CO₂R^(a),     —(C₁₋₄alkylene)₀₋₁S(O)R^(a), —(C₁₋₄alkylene)₀₋₁SO₂R^(a),     —C(O)NH(R^(a)), —C(O)N(R^(a))₂, or —C(O)C(O)NH(R^(a));     -   wherein each R^(a) is independently     -   (1) alkyl, unsubstituted or substituted with one or more R^(m)         substituents, wherein each R^(m) is independently selected from         the group consisting of deuterium, hydroxy, —NR^(b)R^(c),         alkoxy, cyano, halo, —C(O)alkyl, —CO₂alkyl, —CONR^(b)R^(c),         —S(O)alkyl, —SO₂alkyl, —SO₂NR^(b)R^(c), aryl, heteroaryl,         cycloalkyl, heterocycloalkyl, phenoxy, and —O-alkyl-OH;         -   wherein R^(h) is H or alkyl;         -   R^(c) is 1-1, alkyl, alkoxyalkyl, haloalkyl, —C(O)alkyl,             —CO₂alkyl, —SO₂alkyl, —C(O)NH₂, or C(O)H; and         -   each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl             group within R^(m) is unsubstituted or substituted with one             or more substituents independently selected from the group             consisting of alkyl, haloalkyl, hydroxy, NR^(b)R^(c),             alkoxy, haloalkoxy, cyano, halo, oxo, —C(O)alkyl, —CO₂alkyl,             —C(O)-heterocycloalkyl, —CONR^(b)R^(c), —S(O)alkyl,             —SO₂alkyl, —SO₂-haloalkyl, —SO₂NR^(b)R^(c), aryl,             heteroaryl, cycloalkyl, and heterocycloalkyl; or two             substituents taken together form a fused phenyl, heteroaryl,             cycloalkyl, or heterocycloalkyl ring;             -   wherein each alkyl or alkoxy is unsubstituted or                 substituted with —NR^(b)R^(c), heterocycloalkyl,                 heteroaryl, or —C(O)alkyl; and             -   each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl                 is unsubstituted or substituted with alkyl, halo, oxo,                 —C(O)alkyl;     -   (2) phenyl, cycloalkyl, heteroaryl, or heterocycloalkyl, each         unsubstituted or substituted with one or more R^(g)         substituents;         -   wherein each R^(g) is independently selected from the group             consisting of alkyl, haloalkyl, hydroxy, —NR^(b)R^(c),             alkoxy, haloalkoxy, cyano, halo, oxo, —C(O)alkyl, —CO₂alkyl,             —C(O)-heterocycloalkyl, —CONR^(b)R^(c), —S(O)alkyl,             —SO₂alkyl, —SO₂-haloalkyl, —SO₂NR^(b)R^(c), aryl,             heteroaryl, cycloalkyl, and heterocycloalkyl; or two R^(g)             substituents taken together form a fused phenyl, heteroaryl,             cycloalkyl, or heterocycloalkyl ring;             -   wherein each alkyl or alkoxy is unsubstituted or                 substituted with phenyl, —NR^(b)R^(c), heterocycloalkyl,                 heteroaryl, or —C(O)alkyl; and             -   each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl                 is unsubstituted or substituted with alkyl, halo,                 —CO₂alkyl, or —C(O)alkyl; or     -   (3) —NR^(x)R^(y),         -   where R^(x) is H or alkyl; and         -   R^(y) is H, alkyl, alkoxyalkyl, haloalkyl, —C(O)alkyl,             —CO₂alkyl, or —SO₂alkyl; -   R² and R³ are each independently H or deuterium; and -   n is 1 or 2; -   and stereoisomers thereof, and pharmaceutically acceptable salts of     such compounds and stereoisomers.

In a further aspect, the invention relates to pharmaceutical compositions each comprising an effective amount of at least one compound of Formula I or a pharmaceutically acceptable salt of a compound of Formula I. Pharmaceutical compositions according to the invention may further comprise at least one pharmaceutically acceptable excipient.

In another aspect, the invention is directed to a method of treating a subject suffering from a disease or medical condition mediated by NAMPT activity, comprising administering to the subject in need of such treatment an effective amount of at least one compound of Formula I or a pharmaceutically acceptable salt of a compound of Formula I, or comprising administering to the subject in need of such treatment an effective amount of a pharmaceutical composition comprising an effective amount of at least one compound of Formula I or a pharmaceutically acceptable salt of a compound of Formula I.

An aspect of the present invention concerns the use of compound of Formula I for the preparation of a medicament used in the treatment, prevention, inhibition or elimination of cancer.

An aspect of the present invention concerns the use of a compound of Formula I for the preparation of a medicament used in the treatment, prevention, inhibition or elimination of cancer, where the cancer can be selected from leukemia, lymphoma, ovarian cancer, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, CNS cancer, bladder cancer, pancreatic cancer and Hodgkin's disease.

An aspect of the present invention concerns the use of a compound of Formula I for the preparation of a medicament used in the treatment, prevention, inhibition or elimination of cancer, where the cancer can be selected from cancers with solid and liquid tumors, non-small cell lung cancer, leukemia, lymphoma, ovarian cancer, glioma, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, rhino-gastric tumors, colorectal cancer, CNS cancer, bladder cancer, pancreatic cancer and Hodgkin's disease.

In another aspect, the compounds of Formula I and pharmaceutically acceptable salts thereof are useful as NAMPT modulators. Thus, the invention is directed to a method for modulating NAMPT activity, including when NAMPT is in a subject, comprising exposing NAMPT to an effective amount of at least one compound of Formula I or a pharmaceutically acceptable salt of a compound of Formula I.

In yet another aspect, the present invention is directed to methods of making compounds of Formula I and pharmaceutically acceptable salts thereof.

In certain embodiments of the compounds, pharmaceutical compositions, and methods of the invention, the compound of Formula I is a compound selected from those species described or exemplified in the detailed description below, or is a pharmaceutically acceptable salt of such a compound.

Additional embodiments, features, and advantages of the invention will be apparent from the following detailed description and through practice of the invention.

DETAILED DESCRIPTION AND PARTICULAR EMBODIMENTS

For the sake of brevity, the disclosures of the publications cited in this specification, including patents and patent applications, are herein incorporated by reference in their entirety.

Most chemical names were generated using IUPAC nomenclature herein. Some chemical names were generated using different nomenclatures or alternative or commercial names known in the art. In the case of conflict between names and structures, the structures prevail.

General Definitions

As used above, and throughout this disclosure, the following terms, unless otherwise indicated, shall be understood to have the following meanings. If a definition is missing, the conventional definition as known to one skilled in the art controls. If a definition provided herein conflicts or is different from a definition provided in any cited publication, the definition provided herein controls.

As used herein, the terms “including”, “containing” and “comprising” are used in their open, non-limiting sense.

As used herein, the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.

To provide a more concise description, some of the quantitative expressions given herein are not qualified with the term “about”. It is understood that, whether the term “about” is used explicitly or not, every quantity given herein is meant to refer to the actual given value, and it is also meant to refer to the approximation to such given value that would reasonably be inferred based on the ordinary skill in the art, including equivalents and approximations due to the experimental and/or measurement conditions for such given value. Whenever a yield is given as a percentage, such yield refers to a mass of the entity for which the yield is given with respect to the maximum amount of the same entity that could be obtained under the particular stoichiometric conditions. Concentrations that are given as percentages refer to mass ratios, unless indicated differently.

Definitions

As used herein, “alkyl” refers to a saturated, straight- or branched-chain hydrocarbon group having from 1 to 10 carbon atoms. Representative alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, and the like, and longer alkyl groups, such as heptyl, octyl, and the like. As used herein, “lower alkyl” means an alkyl having from 1 to 6 carbon atoms.

The term “alkoxy” as used herein includes —O-(alkyl), wherein alkyl is defined above.

As used herein, “alkoxyalkyl” means -(alkylenyl)-O-(alkyl), wherein each “alkyl” is independently an alkyl group defined above.

The term “amino” as used herein refers to an —NH group.

The term “alkylamino” as used herein denotes an amino group as defined above wherein one hydrogen atom of the amino group is replaced by an alkyl group as defined herein. Aminoalkyl groups can be defined by the following general formula —NH-alkyl. This general formula includes groups of the following general formulae: —NH—C₁-C₁₀-alkyl and —NH—C₁-C₆-alkyl. Examples of aminoalkyl groups include, but are not limited to aminomethyl, aminoethyl, aminopropyl, aminobutyl.

The term “dialkylamino” as used herein denotes an amino group as defined above wherein two hydrogen atoms of the amino group are replaced by alkyl groups as defined herein. Diaminoalkyl groups can be defined by the following general formula —N(alkyl)₂, wherein the alkyl groups can be the same or can be different and can be selected from alkyls as defined herein, for example C₁-C₁₀-alkyl or C₁-C₆-alkyl.

“Aryl” means a mono-, bi-, or tricyclic aromatic group, wherein all rings of the group are aromatic. For bi- or tricyclic systems, the individual aromatic rings are fused to one another. Exemplary aryl groups include, but are not limited to, phenyl, naphthalene, and anthracene.

“Aryloxy” as used herein refers to an —O-(aryl) group, wherein aryl is defined as above.

“Arylalkyl” as used herein refers to an -(alkylenyl)-(aryl) group, wherein alkylenyl and aryl are as defined above. Non-limiting examples of arylalkyls comprise a lower alkyl group. Non-limiting examples of suitable arylalkyl groups include benzyl, 2-phenethyl, and naphthalenylmethyl.

“Arylalkoxy” as used herein refers to an —O-(alkylenyl)-aryl group wherein alkylenyl and aryl are as defined above.

The term “cyano” as used herein means a substituent having a carbon atom joined to a nitrogen atom by a triple bond.

The term “deuterium” as used herein means a stable isotope of hydrogen having one proton and one neutron.

The term “halogen” as used herein refers to fluorine, chlorine, bromine, or iodine. The term “halo” represents chloro, fluoro, bromo, or iodo. Halo can also denote chloro, fluoro, or bromo.

The term “haloalkyl” denotes an alkyl group as defined above wherein one or more, for example one, two, or three of the hydrogen atoms of the alkyl group are replaced by a halogen atom, for example fluoro, bromo, or chloro, in particular fluoro. Examples of haloalkyl include, but are not limited to, monofluoro-, difluoro-, or trifluoro-methyl, -ethyl or -propyl, for example, 3,3,3-trifluoropropyl, 2-fluoroethyl, 2,2,2-trifluoroethyl, fluoromethyl, difluoromethyl, or trifluoromethyl, or bromoethyl or chloroethyl. Similarly, the term “fluoroalkyl” refers to an alkyl group as defined above substituted with one or more, for example one, two, or three fluorine atoms.

The term “haloalkoxy” as used herein refers to an —O-(haloalkyl) group wherein haloalkyl is defined as above. Exemplary haloalkoxy groups are bromoethoxy, chloroethoxy, trifluoromethoxy and 2,2,2-trifluoroethoxy.

The term “hydroxy” means an —OH group.

The term “hydroxyalkyl” denotes an alkyl group that is substituted by at least one hydroxy group, for example, one, two or three hydroxy group(s). The alkyl portion of the hydroxyalkyl group provides the connection point to the remainder of a molecule. Examples of hydroxyalkyl groups include, but are not limited to, hydroxymethyl, hydroxyethyl, 1-hydroxypropyl, 2-hydroxyisopropyl, 1,4-dihydroxybutyl, and the like.

The term “oxo” means an ═O group and may be attached to a carbon atom or a sulfur atom. The term “N-oxide” refers to the oxidized form of a nitrogen atom.

As used herein, the term “cycloalkyl” refers to a saturated or partially saturated, monocyclic, fused polycyclic, bridged polycyclic, or spiro polycyclic carbocycle having from 3 to 15 ring carbon atoms. A non limiting category of cycloalkyl groups are saturated or partially saturated, monocyclic carbocycles having from 3 to 6 carbon atoms. Illustrative examples of cycloalkyl groups include, but are not limited to, the following moieties:

The term “cycloalkoxy” refers to a —O-(cycloalkyl) group.

“Heterocycloalkyl” as used herein refers to a monocyclic, or fused, bridged, or spiro polycyclic ring structure that is saturated or partially saturated and has from 3 to 12 ring atoms selected from carbon atoms and up to three heteroatoms selected from nitrogen, oxygen, and sulfur. The ring structure may optionally contain up to two oxo groups on carbon or sulfur ring members. Heterocycloalkyl groups also include monocyclic rings having 5 to 6 atoms as ring members, of which 1, 2, or 3 ring members are selected from N, S, or O and the rest are carbon atoms A “nitrogen-linked” heterocycloalkyl is attached to the parent moiety via a nitrogen ring atom. A “carbon-linked” heterocycloalkyl is attached to the parent moiety via a carbon ring atom. Illustrative heterocycloalkyl entities include, but are not limited to;

As used herein, the term “heteroaryl” refers to a monocyclic, or fused polycyclic, aromatic heterocycle having from three to 15 ring atoms that are selected from carbon, oxygen, nitrogen, and sulfur. Suitable heteroaryl groups do not include ring systems that must be charged to be aromatic, such as pyrylium. Certain suitable 5-membered heteroaryl rings (as a monocyclic heteroaryl or as part of a polycyclic heteroaryl) have one oxygen, sulfur, or nitrogen atom, or one nitrogen plus one oxygen or sulfur, or 2, 3, or 4 nitrogen atoms. Certain suitable 6-membered heteroaryl rings (as a monocyclic heteroaryl or as part of a polycyclic heteroaryl) have 1, 2, or 3 nitrogen atoms. Examples of heteroaryl groups include, but are not limited to, pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, oxadiazolyl, triazolyl, thiadiazolyl, furazanyl, benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, and furopyridinyl.

The term “bicyclic heteroaryl” refers to a heteroaryl as defined above, having two constituent aromatic rings, wherein the two rings are fused to one another and at least one of the rings is a heteroaryl as defined above. Bicyclic heteroaryls include bicyclic heteroaryl groups comprising 1, 2, 3, or 4 heteroatom ring members and are unsubstituted or substituted with one or more substituents selected from the group consisting of amino and halo; and wherein one or more N atoms of said heteroaryl is optionally an N-oxide. Bicyclic heteroaryls also include 8-, 9-, or 10-membered bicyclic heteroaryl groups. Bicyclic heteroaryls also include 8-, 9-, or 10-membered bicyclic heteroaryl groups that have 1, 2, 3 or 4 heteroatom ring members and that are unsubstituted or substituted with one or more substituents selected from the group consisting of amino and halo; and wherein one or more N atoms of said heteroaryl is optionally an N-oxide. Illustrative examples of bicyclic heteroaryls include, but are not limited to:

The term “five- or six-membered nitrogen-linked heterocycloalkyl ring fused to a phenyl or monocyclic heteroaryl, wherein said phenyl or heteroaryl is unsubstituted or is substituted with amino” include, but are not limited to, the following groups:

Those skilled in the art will recognize that the species of heteroaryl, cycloalkyl, and heterocycloalkyl groups listed or illustrated above are not exhaustive, and that additional species within the scope of these defined terms may also be selected.

As used herein, the term “substituted” means that the specified group or moiety bears one or more suitable substituents. As used herein, the term “unsubstituted” means that the specified group bears no substituents. As used herein, the term “optionally substituted” means that the specified group is unsubstituted or substituted by the specified number of substituents. Where the term “substituted” is used to describe a structural system, the substitution is meant to occur at any valency-allowed position on the system.

As used herein, the expression “one or more substituents” denotes one to the maximum possible number of substitution(s) that can occur at any valency-allowed position on the system. In a certain embodiment, one or more substituents means 1, 2, 3, 4, or 5 substituents. In another embodiment, one or more substituent means 1, 2, or 3 substituents. Such substituents may be the same or different from one another.

Any atom that is represented herein with an unsatisfied valence is assumed to have the sufficient number of hydrogen atoms to satisfy the atom's valence.

When any variable (e.g., alkyl, alkylenyl, heteroaryl, R¹, R², R^(a), etc.) appears in more than one place in any formula or description provided herein, the definition of that variable on each occurrence is independent of its definition at every other occurrence.

Numerical ranges, as used herein, are intended to include sequential whole numbers. For example, a range expressed as “from 0 to 4” or “0-4” includes 0, 1, 2, 3 and 4.

When a multifunctional moiety is shown, the point of attachment to the core is indicated by a line or hyphen. For example, aryloxy- refers to a moiety in which an oxygen atom is the point of attachment to the core molecule while aryl is attached to the oxygen atom.

As used herein, the term “subject” encompasses mammals and non-mammals. Examples of mammals include, but are not limited to, any member of the Mammalian class: humans; non-human primates such as chimpanzees, and other apes and monkey species; farm animals such as cattle, horses, sheep, goats, swine; domestic animals such as rabbits, dogs, and cats; and laboratory animals including rodents, such as rats, mice and guinea pigs, and the like. Examples of non-mammals include, but are not limited to, birds, fish and the like. In one embodiment of the present invention, the mammal is a human.

“Patient” includes both human and animals.

The term “inhibitor” refers to a molecule such as a compound, a drug, an enzyme activator, or a hormone that blocks or otherwise interferes with a particular biologic activity.

The term “modulator” refers to a molecule, such as a compound of the present invention, that increases or decreases, or otherwise affects the activity of a given enzyme or protein.

The terms “effective amount” or “therapeutically effective amount” refer to a sufficient amount of the agent to provide the desired biological result. That result can be reduction and/or alleviation of the signs, symptoms, or causes of a disease or medical condition, or any other desired alteration of a biological system. For example, an “effective amount” for therapeutic use is the amount of a compound, or of a composition comprising the compound, that is required to provide a clinically relevant change in a disease state, symptom, or medical condition. An appropriate “effective” amount in any individual case may be determined by one of ordinary skill in the art using routine experimentation. Thus, the expression “effective amount” generally refers to the quantity for which the active substance has a therapeutically desired effect.

As used herein, the terms “treat” or “treatment” encompass both “preventative” and “curative” treatment. “Preventative” treatment is meant to indicate a postponement of development of a disease, a symptom of a disease, or medical condition, suppressing symptoms that may appear, or reducing the risk of developing or recurrence of a disease or symptom. “Curative” treatment includes reducing the severity of or suppressing the worsening of an existing disease, symptom, or condition. Thus, treatment includes ameliorating or preventing the worsening of existing disease symptoms, preventing additional symptoms from occurring, ameliorating or preventing the underlying metabolic causes of symptoms, inhibiting the disorder or disease, e.g., arresting the development of the disorder or disease, relieving the disorder or disease, causing regression of the disorder or disease, relieving a condition caused by the disease or disorder, or stopping the symptoms of the disease or disorder.

Additional Chemical Descriptions

Any formula given herein is intended to represent compounds having structures depicted by the structural formula as well as certain variations or forms. For example, compounds of any formula given herein may have asymmetric or chiral centers and therefore exist in different stereoisomeric forms. All stereoisomers, including optical isomers, enantiomers, and diastereomers, of the compounds of the general formula, and mixtures thereof, are considered to fall within the scope of the formula. Furthermore, certain structures may exist as geometric isomers (i.e., cis and trans isomers), as tautomers, or as atropisomers. All such isomeric forms, and mixtures thereof, are contemplated herein as part of the present invention. Thus, any formula given herein is intended to represent a racemate, one or more enantiomeric forms, one or more diastereomeric forms, one or more tautomeric or atropisomeric forms, and mixtures thereof.

Diastereomeric mixtures may be separated into their individual diastereomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as, for example, by chromatography and/or fractional crystallization. Enantiomers may be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g., chiral auxiliary such as a chiral alcohol or Mosher's acid chloride, or formation of a mixture of diastereomeric salts), separating the diastereomers and converting (e.g., hydrolyzing or de-salting) the individual diastereomers to the corresponding pure enantiomers. Enantiomers may also be separated by use of chiral HPLC column. The chiral centers of compounds of the present invention may be designated as “R” or “S” as defined by the IUPAC 1974 Recommendations.

The compounds of the invention can form pharmaceutically acceptable salts, which are also within the scope of this invention. A “pharmaceutically acceptable salt” refers to a salt of a free acid or base of a compound of Formula I that is non-toxic, is physiologically tolerable, is compatible with the pharmaceutical composition in which it is formulated, and is otherwise suitable for formulation and/or administration to a subject. Reference to a compound herein is understood to include reference to a pharmaceutically acceptable salt of said compound unless otherwise indicated.

Compound salts include acidic salts formed with inorganic and/or organic acids, as well as basic salts formed with inorganic and/or organic bases. In addition, where a given compound contains both a basic moiety, such as, but not limited to, a pyridine or imidazole, and an acidic moiety, such as, but not limited to, a carboxylic acid, one of skill in the art will recognize that the compound may exist as a zwitterion (“inner salt”); such salts are included within the term “salt” as used herein. Salts of the compounds of the invention may be prepared, for example, by reacting a compound with an amount of a suitable acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilization.

Exemplary salts include, but are not limited, to sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate (“mesylate”), ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate (i.e., 1,1′-methylene-bis(2-hydroxy-3-naphthoate)) salts. A pharmaceutically acceptable salt may involve the inclusion of another molecule such as an acetate ion, a succinate ion or other counterion. The counterion may be any organic or inorganic moiety that stabilizes the charge on the parent compound. Furthermore, a pharmaceutically acceptable salt may have more than one charged atom in its structure. Instances where multiple charged atoms are part of the pharmaceutically acceptable salt can have multiple counterions. Hence, a pharmaceutically acceptable salt can have one or more charged atoms and/or one or more counter ion.

Exemplary acid addition salts include acetates, ascorbates, benzoates, benzenesulfonates, bisulfates, borates, butyrates, citrates, camphorates, camphorsulfonates, fumarates, hydrochlorides, hydrobromides, hydroiodides, lactates, maleates, methanesulfonates, naphthalenesulfonates, nitrates, oxalates, phosphates, propionates, salicylates, succinates, sulfates, tartarates, thiocyanates, toluenesulfonates (also known as tosylates,) and the like.

Exemplary basic salts include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (for example, organic amines) such as dicyclohexylamines, t-butyl amines, and salts with amino acids such as arginine, lysine and the like. Basic nitrogen-containing groups may be quarternized with agents such as lower alkyl halides (e.g. methyl, ethyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g. dimethyl, diethyl, and dibutyl sulfates), long chain halides (e.g. decyl, lauryl, and stearyl chlorides, bromides and iodides), aralkyl halides (e.g. benzyl and phenethyl bromides), and others.

Additionally, acids and bases which are generally considered suitable for the formation of pharmaceutically useful salts from pharmaceutical compounds are discussed, for example, by P. Stahl et al, Camille G. (eds.) Handbook of Pharmaceutical Salts. Properties, Selection and Use. (2002) Zurich: Wiley-VCH; S. Berge et al, Journal of Pharmaceutical Sciences (1977) 66(1) 1-19; P. Gould, International J. of Pharmaceutics (1986) 33 201-217; Anderson et al, The Practice of Medicinal Chemistry (1996), Academic Press, New York; and in The Orange Book (Food & Drug Administration, MD, available from FDA). These disclosures are incorporated herein by reference thereto.

Additionally, any compound described herein is intended to refer also to any unsolvated form, or a hydrate, solvate, or polymorph of such a compound, and mixtures thereof, even if such forms are not listed explicitly. “Solvate” means a physical association of a compound of the invention with one or more solvent molecules. This physical association involves varying degrees of ionic and covalent bonding, including hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of a crystalline solid. “Solvate” encompasses both solution-phase and isolatable solvates. Suitable solvates include those formed with pharmaceutically acceptable solvents such as water, ethanol, and the like. In some embodiments, the solvent is water and the solvates are hydrates.

One or more compounds of the invention may optionally be converted to a solvate. Methods for the preparation of solvates are generally known. Thus, for example, M. Caira et al., J. Pharmaceutical Sci., 93(3), 601-611 (2004), describes the preparation of the solvates of the antifungal fluconazole in ethyl acetate as well as from water. Similar preparations of solvates, hemisolvate, hydrates, and the like are described by F. C. van Tonder et al, AAPS PharmSciTech., 5(1), article 12 (2004); and A. L. Bingham et al, Chem. Commun., 603-604 (2001). A typical, non-limiting process involves dissolving the inventive compound in a suitable amounts of the solvent (organic solvent or water or a mixture thereof) at a higher than ambient temperature, and cooling the solution at a rate sufficient to form crystals which are then isolated by standard methods. Analytical techniques such as, for example, infrared spectroscopy, show the presence of the solvent (or water) in the crystals as a solvate (or hydrate).

The invention also relates to pharmaceutically acceptable prodrugs of the compounds of Formula I, and treatment methods employing such pharmaceutically acceptable prodrugs. The term “prodrug” means a precursor of a designated compound that, following administration to a subject, yields the compound in vivo via a chemical or physiological process such as solvolysis or enzymatic cleavage, or under physiological conditions (e.g., a prodrug on being brought to physiological pH is converted to the compound of Formula I). A “pharmaceutically acceptable prodrug” is a prodrug that is non-toxic, biologically tolerable, and otherwise suitable for formulation and/or administration to the subject. Illustrative procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in “Design of Prodrugs”, ed. H. Bundgaard, Elsevier, 1985.

Examples of prodrugs include pharmaceutically acceptable esters of the compounds of the invention, which are also considered to be part of the invention. Pharmaceutically acceptable esters of the present compounds include the following groups: (I) carboxylic acid esters obtained by esterification of the hydroxy groups, in which the non-carbonyl moiety of the carboxylic acid portion of the ester grouping is selected from straight or branched chain alkyl (for example, acetyl, n-propyl, t-butyl, or n-butyl), alkoxyalkyl (for example, methoxymethyl), aralkyl (for example, benzyl), aryloxyalkyl (for example, phenoxymethyl), aryl (for example, phenyl optionally substituted with, for example, halogen, C₁₋₄alkyl, or C₁₋₄alkoxy or amino); (2) sulfonate esters, such as alkyl- or aralkylsulfonyl (for example, methanesulfonyl); (3) amino acid esters (for example, L-valyl or L-isoleucyl); (4) phosphonate esters and (5) mono-, di- or triphosphate esters. The phosphate esters may be further esterified by, for example, a C₁₋₂₀ alcohol or reactive derivative thereof, or by a 2,3-di(C₆₋₂₄)acyl glycerol. Additional discussion of prodrugs is provided in T. Higuchi and V. Stella, Pro-drugs as Novel Delivery Systems (1987) 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, (1987) Edward B. Roche. ed., American Pharmaceutical Association and Pergamon Press.

For example, if a compound of Formula I contains a carboxylic acid functional group, a prodrug can comprise an ester formed by the replacement of the hydrogen atom of the acid group with a group such as, for example, (C₁-C₈)alkyl, (C₂-C₁₂)alkanoyloxymethyl, 1-(alkanoyloxy)ethyl having from 4 to 9 carbon atoms, 1-methyl-1-(alkanoyloxy)-ethyl having from 5 to 10 carbon atoms, alkoxycarbonyloxymethyl having from 3 to 6 carbon atoms, 1-(alkoxycarbonyloxy)ethyl having from 4 to 7 carbon atoms, 1-methyl-1-(alkoxycarbonyloxy)ethyl having from 5 to 8 carbon atoms, N-(alkoxycarbonyl)aminomethyl having from 3 to 9 carbon atoms, 1-(N-(alkoxycarbonyl)amino)ethyl having from 4 to 10 carbon atoms, 3-phthalidyl, 4-crotonolactonyl, gamma-butyrolacton-4-yl, di-N,N—(C₁-C₂)alkylamino(C₂-C₃)alkyl (such as β-dimethylaminoethyl), carbamoyl-(C₁-C₂)alkyl, N,N-di(C₁-C₂)alkylcarbamoyl-(C₁-C₂)alkyl and piperidino-, pyrrolidino- or morpholine (C₂-C₃)alkyl, and the like.

Similarly, if a compound of Formula I contains an alcohol functional group, a prodrug can be formed by the replacement of the hydrogen atom of the alcohol group with a group such as, for example, (C₁-C₆)alkanoyloxymethyl, 1-((C₁-C₆)alkanoyloxy)ethyl, 1-methyl-1-((C₁-C₆)alkanoyloxy)ethyl, (C₁-C₆)alkoxycarbonyloxymethyl, N—(C₁-C₆)alkoxycarbonylaminomethyl, succinoyl, (C₁-C₆)alkanoyl, α-amino(C₁-C₄)alkanyl, arylacyl and α-aminoacyl, or α-aminoacyl-α-aminoacyl, where each α-aminoacyl group is independently selected from the naturally occurring L-amino acids, P(O)(OH)₂, —P(O)(O(C₁-C₆)alkyl)₂ or glycosyl (the radical resulting from the removal of a hydroxyl group of the hemiacetal form of a carbohydrate), and the like.

If a compound of Formula I incorporates an amine functional group, a prodrug can be formed by the replacement of a hydrogen atom in the amine group with a group such as, for example, R″-carbonyl, R″O-carbonyl, NR″R′-carbonyl where R″ and R′ are each independently (C₁-C₁₀)alkyl, (C₃-C₇) cycloalkyl, benzyl, or R″-carbonyl is a natural α-aminoacyl or natural α-aminoacyl, —C(OH)C(O)OY¹ wherein Y¹ is H, (C₁-C₆)alkyl or benzyl, —C(OY²)Y³ wherein Y² is (C₁-C₄) alkyl and Y³ is (C₁-C₆)alkyl, carboxy(C₁-C₆)alkyl, amino(C₁-C₄)alkyl or mono-N— or di-N,N—(C₁—C₆)alkylaminoalkyl, —C(Y⁴)Y⁵ wherein Y⁴ is H or methyl and Y⁵ is mono-N- or di-N,N—(C₁-C₆)alkylamino morpholino, piperidin-1-yl or pyrrolidin-1-yl, and the like.

The present invention also relates to pharmaceutically active metabolites of compounds of Formula I, and uses of such metabolites in the methods of the invention. A “pharmaceutically active metabolite” means a pharmacologically active product of metabolism in the body of a compound of Formula I or salt thereof. Prodrugs and active metabolites of a compound may be determined using routine techniques known or available in the art. See, e.g., Bertolini et al. J. Med. Chem. 1997, 40, 2011-2016; Shan et al., J. Pharm. Sci. 1997, 86 (7), 765-767; Bagshawe, Drug Dev. Res. 1995, 34, 220-230; Bodor, Adv. Drug Res. 1984, 13, 255-331; Bundgaard, Design of Prodrugs (Elsevier Press, 1985): and Larsen, Design and Application of Prodrugs, Drug Design and Development (Krogsgaard-Larsen et al., eds., Harwood Academic Publishers, 1991).

Any formula given herein is also intended to represent unlabeled forms as well as isotopically labeled forms of the compounds. Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, chlorine, and iodine, such as ²H, ³H, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, ³¹P, ³²P, ³⁵S, ¹⁸F, ³⁶Cl, and ¹²⁵I, respectively. Such isotopically labelled compounds are useful in metabolic studies (for example with ¹⁴C), reaction kinetic studies (with, for example ²H or ³H), detection or imaging techniques [such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT)] including drug or substrate tissue distribution assays, or in radioactive treatment of patients. In particular, an ¹⁸F or ¹¹C labeled compound may be particularly suitable for PET or SPECT studies. Further, substitution with heavier isotopes such as deuterium (i.e., ²H) may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements. Isotopically labeled compounds of this invention and prodrugs thereof can generally be prepared by carrying out the procedures disclosed in the schemes or in the examples and preparations described below by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent.

The use of the terms “salt”, “solvate”, “polymorph”, “prodrug”, and the like, with respect to the compounds described herein is intended to apply equally to the salt, solvate, polymorph, and prodrug forms of enantiomers, stereoisomers, rotamers, tautomers, atropisomers, and racemates of the inventive compounds.

Compounds of the Invention

In some embodiments of Formula I, compounds of the invention have the following Formula I-a:

wherein R, R¹, R², and R³ are as defined herein for Formula I.

In some embodiments, R is an unsubstituted or substituted bicyclic heteroaryl as defined for Formula I. In some embodiments, the bicyclic heteroaryl has 1, 2, or 3 nitrogen ring atoms. In other embodiments, the bicyclic heteroaryl is a 9- or 10-membered bicyclic heteroaryl, unsubstituted or substituted as described for Formula I. In other embodiments, the bicyclic heteroaryl is an 8- or 9-membered heteroaryl, unsubstituted or substituted as described for Formula I. In other embodiments, R is a bicyclic heteroaryl selected from the group consisting of:

each unsubstituted or substituted as described for Formula I. In further embodiments, R is selected from the group consisting of:

each unsubstituted or substituted as described for Formula I. In further embodiments, R is selected from the group consisting of:

In further embodiments, R is

In other embodiments, R is a five- or six-membered nitrogen-linked heterocycloalkyl ring fused to an unsubstituted or substituted phenyl or monocyclic heteroaryl, for examples a 6 membered heteroaryl, as defined in Formula I. In further embodiments, R is

In still other embodiments, R is

In other embodiments, R is substituted with one or more substituents selected from the group consisting of amino and halo.

In some embodiments, R¹ is H. In other embodiments, R¹ is —C(O)R^(a), —CO₂R^(a), —S(O)R^(a), or —SO₂R^(a). In further embodiments, R¹ is —C(O)R^(a), —CO₂R^(a), or SO₂R^(a). In other embodiments, R¹ is —C(O)NH(R^(a)) or —C(O)C(O)NH(R^(a)). In other embodiments, R^(a) is alkyl, unsubstituted or substituted as described for Formula I. In other embodiments, R^(a) is —NR^(x)R^(y). In further embodiments, R^(a) is —CH₂C(O)R^(a) or —CH₂SO₂R^(a).

In some embodiments, R^(a) is methyl, ethyl, propyl, isopropyl, tert-butyl, isobutyl, isopentyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, pyrrolyl, furanyl, thiophenyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, triazoyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, isoindolinyl, azetidinyl, oxetanyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, or tetrahydrothiophenyl, each unsubstituted or substituted as described for Formula I. In other embodiments, R^(a) is a bicyclic heteroaryl, unsubstituted or substituted with one or more substituents selected from the group consisting of alkyl, —CO2-tert-butyl, oxo, and halo. In other embodiments, R^(a) is alkyl, phenyl, benzyl, cycloalkyl, or heterocycloalkyl, each unsubstituted or substituted as described for Formula I. In some embodiments, R^(a) is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, 2,2-dimethylpropyl, hydroxyethyl, aminoethyl, cyanoethyl, ethoxy, tert-butoxy, phenyl, benzyl, cyclobutyl, cyclopentyl, cyclohexyl, oxetanyl, pyrrolidinyl, piperidinyl, tetrahydrofuranyl, or tetrahydropyranyl, each unsubstituted or substituted as described for Formula I. In other embodiments, R^(a) is tert-butoxy, 2,2-dimethylpropyl, benzyl, cyclohexyl, tetrahydropyranyl, phenyl, methyl, ethyl, or isopropyl.

In some embodiments, R^(a) is phenyl, cycloalkyl, heteroaryl, or heterocycloalkyl, each unsubstituted or substituted as described for Formula I. In other embodiments, R^(a) is phenyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, pyrrolyl, furanyl, thiophenyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, triazoyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, isoindolinyl, azetidinyl, oxetanyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, or tetrahydrothiophenyl, each unsubstituted or substituted as in Formula I. In other embodiments, R^(a) is phenyl, cycloalkyl, heteroaryl, or heterocycloalkyl, each unsubstituted or substituted with one or more substituents selected from the group consisting of fluoro, oxo, methyl, —CONH₂, acetyl, —SO₂methyl, —C(O)-isopropyl, pyridazinyl, triazolyl, dimethylaminomethyl, cyano, methyl-triazolyl-methoxy, trifluoromethoxy, pyrrolidinylmethyl, acetylamino, tetrazolylmethyl, methyl-tetrazolyl-methyl, methyl-imidazolyl-methyl, —NHSO₂methyl, 1,1-dioxothiomorpholinyl, 4-methyl-piperazinylmethyl, —NHCONH₂, —SO₂CF₃, morpholinylmethyl, imidazolyl, —SO₂NH₂, methylpiperidinyl, methyl-piperazinyl, —C(O)(4-methyl-piperazinyl), morpholinyl, trifluoromethyl, cyclopropyl, ethyl, isoxazolyl, tetrazolyl, isopropyl, phenyl, fluoro-phenyl, tert-butyl, benzyl, N-methylpyrrolidinyl, N-acetyl-pyrrolidinyl, isobutyl, propyl, methylpyrazolyl, trifluoroethyl, pyrimidinyl, oxo, acetyl, cyano, —CO₂-tert-butyl, and amino.

In other embodiments, R¹ is alkyl, unsubstituted or substituted with one or more substituents selected from the group consisting of fluoro, tert-butoxy, —C(O)NMe₂, —NHCHO, methoxy, phenoxy, cyano, acetyl, hydroxy, —OCH₂C(CH₃)═OH, —NH(acetyl), and —N(Me)(acetyl).

In other embodiments, R¹ is —SO₂R^(a), where R^(a) is methyl, ethyl, phenyl, benzyl, or 2,2-dimethylpropyl.

In other embodiments, R¹ is —C(O)NHR^(a), wherein R^(a) is methyl, ethyl, propyl, isopropyl, tertobutyl, cyclohexyl, —CH₂-cyclohexyl, oxetanyl, or methyloxetanyl, or R^(a) is a phenyl or benzyl group, each optionally substituted with one or more substituents selected from the group consisting of cyano, methyl, fluoro, methoxy, and chloro.

In some embodiments, one of R² and R³ is deuterium and the other is H. In other embodiments, both R² and R³ are H.

In some embodiments, each alkyl or alkylene described above is independently a C₁₋₁₀alkyl. In other embodiments, each alkyl or alkylene in Formula I is independently a C₁₋₆alkyl. In still other embodiments, each alkyl or alkylene in Formula I is independently a C₁₋₄alkyl.

In certain embodiments, the compound of Formula I is chosen from the following table:

Ex. Structure Chemical Name 1

tert-butyl 2-[(1,3- dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 2

tert-butyl 2- [(thieno[2,3- c]pyridine-2- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 3

tert-butyl 2- [(imidazo[1,2- a]pyrimidine-6- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 4

tert-butyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 5

tert-butyl 2- [(imidazo[1,2- a]pyridine-6- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 6

N-[[8-(3,3- dimethylbutanoyl)-8- azaspiro[2.5]octan-2- yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 7

N-[[8-(2- phenylacetyl)-8- azaspiro[2.5]octan-2- yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 8

tert-butyl 2-[(1H- pyrrolo[3,2-c]pyridine- 2- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 9

N-[[8- (cyclohexanecarbonyl)- 8-azaspiro[2.5]octan- 2-yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 10

N-[[8- (tetrahydropyran-4- carbonyl)-8- azaspiro[2.5]octan-2- yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 11

N-[(8-benzoyl-8- azaspiro[2.5]octan-2- yl)methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 12

N-[[8-(2- methylpropanoyl)-8- azaspiro[2.5]octan-2- yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 13

N-[[8- (benzenesulfonyl)-8- azaspiro[2.5]octan-2- yl]methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 14

N-[(8-ethylsulfonyl-8- azaspiro[2.5]octan-2- yl)methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 15

tert-butyl 2-[(1H- pyrazolo[3,4- b]pyridine-5- carbonylamino)methyl]- 8-azaspiro[2.5]octane- 8-carboxylate 16

N-[(8-acetyl-8- azaspiro[2.5]octan-2- yl)methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 17

N-[(8-methylsulfonyl- 8-azaspiro[2.5]octan-2- yl)methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 18

N-(8- azaspiro[2.5]octan-2- ylmethyl)-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide 19

N-(8- azaspiro[2.5]octan-2- ylmethyl)-1H- pyrazolo[3,4- b]pyridine-5- carboxamide 20

N-[(8-propanoyl-8- azaspiro[2.5]octan-2- yl)methyl]-1H- pyrrolo[3,2-c]pyridine- 2-carboxamide or 21

tert-butyl 2- ((imidazo[1,2- a]pyridine-6- carboxamido)methyl)- 7-azaspiro[3.5]nonane- 7-carboxylate or a pharmaceutically acceptable salt thereof, or a stereoisomer or a pharmaceutically acceptable salt of said stereoisomer.

In certain other embodiments, the compound of Formula I is chosen from the following table:

Ex. Structure Chemical Name 22

tert-butyl 2-[(imidazo[1,2- a]pyridine-6- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 23

tert-butyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 24

N-[[6-(3,3-dimethylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 25

tert-butyl 2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 26

N-[[6-(2-imidazol-1-ylacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 27

N-[[6-(4,4,4-trifluorobutanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 28

N-[[6-[2-(3- methylsulfonylphenyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 29

N-[[6-(3,3-dimethylbutanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 30

N-[[6-[2-(4-methylpiperazin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl)furo[2,3-c]pyridine- 2-carboxamide 31

N-[[6-[2-(3- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 32

N-[[6-(2-cyclopropylacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 33

N-[[6-(2-pyrrolidin-1-ylacetyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 34

N-[[6-[2-(3-methylisoxazol-5- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 35

N-[[6-[2-(1-piperidyl)acetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 36

N-[[6-(2-tetrahydropyran-4- ylacetyl)-6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 37

N-[[6-(2-tetrahydrofuran-2- ylacetyl)-6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 38

N-[[6-(2-tert-butoxyacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 39

N-[[6-[2-(3-pyridyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 40

N-[[6-[2-[1-(2,2,2- trifluoroethyl)-4- piperidyl]acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 41

tert-butyl 2-[(imidazo[1,2- a]pyridine-6- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 1) 42

tert-butyl 2-[(imidazo[1,2- a]pyridine-6- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 2) 43

tert-butyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 1) 44

tert-butyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 2) 45

N-[[6-(3,3-dimethylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 46

N-[[6-(3-methylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 47

N-[[6-(2-phenylacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 48

tert-butyl 2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 1) 49

tert-butyl 2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate (isomer 2) 50

N-[[6-(2-pyrazin-2-ylacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 51

N-[[6-(2-morpholinoacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 52

N-[[6-(2-tetrahydropyran-2- ylacetyl)-6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 53

N-[[6-(2-pyrrolidin-1- ylpropanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 54

N-[[6-[2-(tert-butylamino)-2- oxo-acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 55

N-[[6-[4-(dimethylamino)-4- oxo-butanoyl]-6- azaspiro[2,5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 56

N-[[6-(1-methyl-5-oxo- pyrrolidine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 57

N-[[6-[2-(2-oxopyrrolidin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 58

N-[[6-(2,2- difluorocyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 59

N-[[6-(tetrahydrofuran-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 60

N-[[6-(tetrahydropyran-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 61

N-[[6-(tetrahydrofuran-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 62

N-[[6-(2-formamidoacetyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 63

N-[[6-[3-(3,5-dimethylpyrazol- 1-yl)propanoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 64

N-[[6-(1-carbamoylpyrrolidine- 2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 65

N-[[6-(3-morpholinopropanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 66

N-[[6-(1,1-dioxothiolane-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 67

N-[[6-[2-(3,5-dimethylpyrazol- 1-yl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 68

N-[[6-(1-acetylpyrrolidine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 69

N-[[6-(2- methylsulfonylbenzoyl)-6- azaspiro[2,5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 70

N-[[6-[3-(1,2,4-triazol-4- yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 71

N-[[6-[4- [(dimethylamino)methyl]benzoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 72

N-[[6-(4-acetamidobenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 73

N-[[6-(1- methylsulfonylpiperidine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 74

N-[[6-(1- methylsulfonylpiperidine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 75

N-[[6-(2-morpholinopropanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 76

N-[[6-(1- methylsulfonylpyrrolidine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 77

N-[[6-[2-(3-oxoisoindolin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 78

N-[[6-(1-carbamoylpiperidine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 79

N-[[6-(1-carbamoylpiperidine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methy]]furo[2,3-c]pyridine- 2-carboxamide 80

N-[[6-[2-(1,1-dioxothiolan-3- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 81

N-[[6-[2-(2,4-dioxopyrimidin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 82

N-[[6-(1-acetylpiperidine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 83

N-[[6-[4-(tetrazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 84

N-[[6-[4- (methanesulfonamido)benzoyl] 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 85

N-[[6-[4-(1,1-dioxo-1,4- thiazinan-4-yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 86

N-[[6-(4-[(4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 87

N-[[6-[2-((4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo(2,3-c]pyridine-2- carboxamide 88

N-[[6-[3-[(4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 89

N-[[6-[3-(4-methylpiperazin-1- yl)propanoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 90

N-[[6-(1-isopropyl-5-oxo- pyrrolidine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 91

N-[[6-[2-(3-oxopiperazin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 92

N-[[6-(3- methylsulfonylbenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 93

N-[[6-(4- methylsulfonylbenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 94

N-[[6-(4-ureidobenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 95

N-[[6-[2-(4-acetylpiperazin-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 96

N-[[6-[4-[(5-methyltetrazol-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 97

N-[[6-(pyridine-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 98

N-[[6-(pyridine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl)methyl]furo[2,3-c]pyridine-2- carboxamide 99

N-[[6-(oxazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl)methyl]furo[2,3-c]pyndine-2- carboxamide 100

N-[[6-(1H-1,2,4-triazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 101

N-[[6-(1H-imidazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 102

N-[[6-(pyrimidine-4-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 103

N-[[6-(pyridine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 104

N-[[6-(1H-pyrazole-3-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 105

N-[[6-(1-methylimidazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 106

N-[[6-(3-methyl-1H-pyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 107

N-[[6-(2-methylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 108

N-[[6-(5-methyl-1H-pyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 109

N-[[6-(1-methylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 110

N-[[6-(pyridazine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 111

N-[[6-(pyrimidine-5-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 112

N-[[6-(pyrazine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 113

N-[[6-(pyridazine-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 114

N-[[6-(1-methylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 115

N-[[6-(1,5-dimethylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 116

N-[[6-(2,5-dimethylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 117

N-[[6-(5-methylisoxazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 118

N-[[6-(4-methyl-1,2,5- oxadiazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 119

N-[[6-(2-methylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 120

N-[[6-(4-methylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine 2-carboxamide 121

N-[[6-(2-methylpyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 122

N-[[6-(5-methylpyrazine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 123

N-[[6-(3-cyclopropyl-1H- pyrazole-5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 124

N-[[6-(1-ethyl-5-methyl- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 125

N-[[6-(3,5-dimethylisoxazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 126

N-[[6-(1-ethylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 127

N-[[6-(6-cyanopyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 128

N-[[6-(2,4-dimethyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 129

N-[[6-(2-morpholinopyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 130

N-[[6-(cyclopropanecarbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 131

N-[[6-[1-methyl-5- (trifluoromethyl)pyrazole-3- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 132

N-[[6-(4-isoxazol-5-yl-1-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 133

N-[[6-(2-acetamidopyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 134

N-[[6-[3-(tetrazol-1-yl)-1H- pyrazole-4-carbonyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 135

N-[[6-(6-acetamidopyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 136

N-[[6-(3-ethyl-5-methyl- isoxazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 137

N-[[6-(2-ethyl-5-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 138

N-[[6-(1-ethyl-3-methyl- pyrazolo-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 139

N-[[6-(3-methylisoxazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 140

N-[[6-[2-methyl-3-(3- methylpyrazol-1-yl)propanoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 141

N-[[6-(1H-pyrazole-4-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2.3-c]pyridine-2- carboxamide 142

N-[[6-[2-(1-methylsulfonyl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 143

N-[[6-(4-methylmorpholine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 144

N-[[6-[1-(2- methylpropanoyl)azetidine-3- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 145

N-[[6-(1-acetylazetidine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 146

N-[[6-(1-pyridazin-3- ylpyrrolidine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 147

N-[[6-[2-(1-pyrimidin-2-yl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 148

N-[[6-[2-(1-isopropyl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 149

N-[[6-[2-(1-methyl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 150

N-[[6-[2-(3-methyloxetan-3- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 151

isopropyl 2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 152

N-[[6-[2-(2- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2- y]]methyl]furo[2,3-c]pyridine-2- carboxamide 153

N-[[6-(3-methoxypropanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 154

N-[[6-[2-[4- (trfluoromethylsulfonyl)phenyl] acetyl]-6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 155

N-[[6-[3- [acetyl(methyl)amino]propanoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 156

N-[[6-[2-(2-pyridyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 157

N-[[6-[(4- cyanophenyl)carbamoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 158

N-[[6-(m- tolylmethylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 159

N-[[6-(p-tolylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 160

N-[[6-(benzylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 161

N-[[6-[(2- fluorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 162

N-[[6-(p-tolylmethylcarbamoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamidc 163

N-[[6-[(4- fluorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 164

N-[[6-[(2- methoxyphenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 165

N-[[6-[(3- methoxyphenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 166

N-[[6-[(3- fluorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 167

N-[[6-[(4- methoxyphenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 168

N-[[6-[(3,4- dichlorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 169

N-[[6-(1-adamantylcarbamoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 170

N-[[6-[(4- chlorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 171

N-[[6-[(2- chlorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 172

N-[[6-(ethylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 173

N-[[6-[(2,4- dichlorophenyl)methylcarbamoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 174

N-[[6-[2-(3-hydroxy-3-methyl- cyclobutyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 175

N-[[6-[2-(3-methyloxetan-3- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 176

N-[[6-[2-(2-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 177

N-[[6-[2-(3-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 178

N-[[6-[2-(3- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 179

N-[[6-[4-(1,2,4-triazol-1- yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 180

N-[[6-[2-(2-methylimidazol-1- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 181

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 182

N-[[6-(tert-butylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2-' carboxamide 183

N-[[6-(isopropylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 184

N-[[6- (cyclohexylmethylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 185

N-[[6-(propylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 186

N-[[6-(cyclohexylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 187

N-[[6-(phenylcarbamoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 188

N-[[6-[2-(1-isopropyl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 189

N-[[6-(3-methylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 190

N-[[6-[2-(4-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 191

N-[[6-(2-cyanoacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 192

ethyl 2-[(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 193

tert-butyl 2-[(1H-pyrrolo[3,2- e]pyridine-2- carbonylamino)methyl]-7- azaspiro[3.5]nonane-7- carboxylate 194

tert-butyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-7- azaspiro[3.5]nonane-7- carboxylate 195

N-[[6-[2-(3-methyloxetan-3- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine 2-carboxamide 196

N-[[6-(2-cyclohexylacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 197

N-[[6-(3-cyclohexylpropanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2 carboxamide 198

N-[[6-(2-morpholinoacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 199

N-[[6-(3-phenylpropanoyl)-6- azaspiro[2.5]octan-2-yl]methyl] 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 200

tert-butyl 2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-7- azaspiro[3.5]nonane-7- carboxylate 201

N-[[6-[2-(3,5- difluorophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 202

N-[[6-[2-[3- (trifluoromethyl)phenyl]acetyl]- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 203

N-[[6-(tert-butylcarbamoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 204

[2,2,2-trideuterio-1,1- bis(trideuteriomethyl)ethyl]2- [(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 205

(2-methoxy-1,1-dimethyl-2-oxo- ethyl) 2-[(furo[2,3-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 206

N-[[6-[2-(3- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 207

N-[[6-[2-(4- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 208

N-[[6-(phenylcarbamoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 209

N-[[6-[3-(3-pyridyl)propanoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 210

N-[[6-(benzylcarbamoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 211

N-[(6-benzylsulfonyl-6- azaspiro[2.5]octan-2-yl)methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 212

N-[[6-(tert-butylcarbamoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 213

N-[[6-(3,3-dimethylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide (isomer 1) 214

N-[[6-(3,3-dimethylbutanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide (isomer 2) 215

(2-hydroxy-1,1-dimethyl-ethyl) 2-[(furo[2,3-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 216

N-[[6-[2-(4- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 218

(2-methoxy-1,1-dimethyl-ethyl) 2-[(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 219

N-[[6-(2-tetrahydropyran-4- ylacetyl)-6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 220

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 221

N-[[6-(1-methylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 222

N-[[6-(1-isopropyl-3,5-dimethyl- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 223

N-[[6-[1-(4-fluorophenyl)-3,5- dimethyl-pyrazole-4-carbonyl]- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 228

(1-methylcyclobutyl)2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 229

N-[[6-(3-morpholinopropanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 230

N-[[6-(2,2-difluoro-2-phenyl- acetyl)-6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 231

N-[[6-(3-methylpyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 232

N-[[6-(3-methylpyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 233

N-[[6-(6-methylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 234

N-[[6-(6-methylpyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 235

N-[[6-(4-methylpyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 236

N-[[6-(1H-benzimidazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 237

N-[[6-(pyrrolo[1,2-c]pyrimidine- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 238

N-[[6-(1H-benzotriazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl)methyl]furo[2,3-c]pyridine- 2-carboxamide 239

N-[[6-(1H-pyrrolo[2,3- b]pyridine-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2 carboxamide 240

N-[[6-(1H-indazole-4-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 241

N-[[6-(1H-benzimidazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 242

N-[[6-(4-cyanobenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 243

N-[[6-(3-cyanobenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 244

N-[[6-[4-[(5-methyl-1,2,4- oxadiazol-3- yl)methoxy]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 245

N-[[6-[4- (morpholinomethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 246

N-[[6-[4-[(2-methylimidazol-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 247

N-[[6-[4- (trifluoromethoxy)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 248

N-[[6-[4-(pyrrolidin-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 249

N-[[6-[3-(1,2,4-triazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 250

N-[[6-[2-(1,2,4-triazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 251

N-[[6-[4-(1,2,4-triazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 252

N-[[6-[3-(imidazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 253

N-[[6-(4-imidazol-1-ylbenzoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 254

N-[[6-[4-(1H-1,2,4-triazol-5- yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 255

N-[[6-(6-imidazol-1-ylpyridine- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 256

N-[[6-[4- (trifluoromethyl)pyridine-2- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 257

N-[[6-[6- (trifluoromethyl)pyridine-3- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 258

N-[[6-(3-oxo-4H-1.4- benzoxazine-6-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 259

N-[[6-(4-sulfamoylbenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 260

N-[[6-[2-(imidazol-1- ylmethyl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 261

N-[[6-(quinoxaline-6-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo(2,3-c]pyridine-2- carboxamide 262

N-[[6-(1,6-naphthyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 263

N-[[6-(2-methyl-1H- benzimidazole-5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo(2,3-c]pyridine-2 carboxamide 264

N-[[6-(3-acetamidobenzoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 265

N-[[6-(3-acetamidopyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 266

N-[[6-(2,1,3-benzoxadiazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 267

N-[[6-(1,8-naphthyridine-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 268

N-[[6-(isoquinolinc-5-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyndme-2- carboxamide 269

N-[[6-(quinoxaline-2-carbonyl)- 6-azaspiro[2.5]octan-2- yl]mcthyl]furo[2,3-c]pyridine-2- carboxamide 270

N-[[6-(1,5-naphthyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 271

N-[[6-(1,8-naphthyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 272

N-[[6-(isoxazole-5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 273

N-[[6-(3-methylbutanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo(2,3-c]pyridine-2- carboxamide 274

tert-butyl 2-[(4,6-dihydro-1H- pyrrolo[3,4-c]pyrazole-5- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 275

N-[[6-[2-(1,4-dimethyl-4- piperidyl)acetyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2.3-c]pyridine-2- carboxamide 276

N-[[6-[2-(3-hydroxy-3-methyl- cyclobutyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 277

N-[[6-[2-(3-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 278

N-[[6-[2-(4-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 279

N-[[6-(1,3-dimethylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 280

N-[[6-[4-(2-methyltetrazol-5- yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 281

N-[[6-(4,6-dimethylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 282

N-[[6-(4-oxopentanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine]-2- carboxamide 283

N-[[6-(4-hydroxy-4-methyl- pentanoyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 284

N-[[6-(3-hydroxy-3-methyl- butanoyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 285

N-[[6-[2-(2-pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo(3,2-c]pyridine-2- carboxamide 286

N-[[6-(2-pyrimidin-2-ylacetyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 287

N-[[6-(2-pyrazin-2-ylacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 288

N-[[6-(3-thiazol-2-ylpropanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3 dihydropyrrolo[3,4-c]pyridine-2- carboxamide 289

N-[[6-(2-phenoxyacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 290

N-[[6-(3-tetrahydropyran-4- ylpropanoyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 291

N-[[6-(4-methylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 292

N-[[6-(3,5-dimethyl-1H- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 293

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 294

N-[[6-(1-tert-butyl-3,5-dimethyl- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 295

N-[[6-(1-benzyl-3,5-dimethyl- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 296

N-[[6-(5-tert-butyl-2-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 297

N-[[6-(2-ethylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 298

N-[[6-(2-tert-butyl-4-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 299

N-[[6-(2,4-dimethylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 300

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide (isomer 1) 301

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide (isomer 2) 302

N-[[6-(1H-indazole-3-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 303

N-[[6-[1-(1-isopropylpyrrolidin- 3-yl)pyrazole-4-carbonyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 304

N-[[6-[1-(1-acetylpyrrolidin-3- yl)pyrazole-4-carbonyl]-6- azaspiro[2.5]octan-2- yl]mcthyl]furo[2,3-c]pyridine-2 carboxamide 305

N-[[6-[5-(1,3-dimethylpyrazol- 4-yl)isoxazole-3-carbonyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2 carboxamide 306

tert-butyl 3-[2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6-carbonyl]- 4,6-dihydro-1H-pyrrolo[3,4- c]pyrazole-5-carboxylate 307

N-[[6-[1-(1-methylpyrrolidin-3 yl)pyrazole-4-carbonyl]-6- azaspiro[2.5]octan-2- yl)methyl]furo[2,3-c]pyridine-2- carboxamide 308

N-[[6-(2-tert-butyl-5-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 309

N-[[6-(2-methylimidazo[1,2- a]pyridine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 310

N-[[6-(6-methyl-1H- benzimidazole-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 311

N-[[6-(5-methylimidazo[1,2- a]pyridine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 312

N-[[6-(6-fluoro-1H-indazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 313

N-[[6-(pyrazolo[1,5- a]pyrimidine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 314

N-[[6-(1-ethyl-3,5-dimethyl- pyrazole-4-carhonyl)-6- azaspiro[2.5]octan-2- yl]meihyl]furo[2,3-c]pyridine-2- carboxamide 315

N-[[6-(6-methylimidazo[1,2- a]pyridine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 316

N-[[6-(pyrazolo[1,5-a]pyridine- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 317

N-[[6-(imidazo[1,2-a]pyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 318

N-[[6-(5-isopropylisoxazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 319

N-[[6-(3-isobutyl-1H-pyrazole- 5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 320

N-[[6-(imidazo[1,2- a]pyrimidine-2-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 321

N-[[6-(pyrazolo[1,5- a]pyrimidine-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 322

N-[[6-(3-tert-butyl-1H-pyrazole- 5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 323

N-[[6-(5-isopropyl-1H-pyrazole- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 324

N-[[6-(3-isopropyl-1H-pyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 325

N-[[6-(2-isopropylpyrazole-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl)furo[2,3-c]pyridine- 2-carboxamide 326

N-[[6-(5-ethyl-2-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyndine-2- carboxamide 327

N-[[6-(5-cyclopropylisoxazole- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 328

N-[[6-(5-cyclopropylisoxazole- 4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 329

N-[[6-(3,5-dimethyl-1H- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 330

N-[[6-(1,5-dimethylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 331

N-[[6-(4-methyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 332

N-[[6-(3-cyclopropyl-1H- pyrazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2 carboxamide 333

N-[[6-(1,4,5,6- tetrahydrocyclopenta[c]pyrazole- 3-carbonyl)-6- azaspiro[2.5]octan-2- yl[methyl]furo[2,3-c]pyridine-2- carboxamide 334

N-[[6-(2,5-dimethyloxazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 335

N-[[6-(1,3-dimethylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 336

N-[[6-(oxazole-5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 337

N-[[6-(isoxazole-4-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 338

N-[[6-(1H-imidazole-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 339

N-[[6-[4-(4-methylpiperazin-1- yl)benzoyl]-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 340

N-[[6-(3H-imidazo[4,5- b]pyridine-6-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 341

N-[[6-(5-methylpyridine-2- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide 343

N-[[6-[4-[(4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 344

N-[[6-[3-[(4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 345

N-[[6-[4- [(dimethylamino)methyl]benzoyl]- 6-azaspiro[2.5]octan-2- yl]methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 346

N-[[6-[4-[(4-methylpiperazin-1- yl)methyl]benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 347

N-[[6-(1,5-dimethylpyrazole-4- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 348

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 350

(3-methyloxetan-3-yl)2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 351

(2-hydroxy-1,1-dimethyl-ethyl) 2-[(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl)-6- azaspiro[2.5]octane-6- carboxylate 352

N-[[6-(4-methylpyridine-3- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 353

N-[[6-(3-cyclopropyl-1H- pyrazole-5-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl)- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 354

N-[[6-(4-isoxazol-5-yl-1-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2-yl)methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 355

N-[[6-(2,4-dimethyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 356

N-[[6-[2-(1,4-dimethyl-4- piperidyl)acetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 357

N-[[6-[2-(2- cyanophenyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 358

(2-acetamido-1,1-dimethyl- ethyl)2-[(1,3- dihydropyrrolo[3,4-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 359

N-[[6-(2-thiazol-2-ylacetyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 360

N-[[6-(4-hydroxy-4-methyl- pentanoyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 361

N-[[6-((3-methyloxetan-3- yl)carbamoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 362

N-[[6-[4-(4-methylpiperazin-1- yl)benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 363

N-[[6-[4-(4-methylpiperazin-1- yl)benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 364

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 365

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide (isomer 1) 366

N-[[6-(1,3,5-trimethylpyrazole- 4-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide (isomer 2) 367

tert-butyl 2-[[(1,1,3,3- tetradeuteriopyrrolo[3,4- c]pyridine-2- carbonyl)amino]methyl]-6- azaspiro[2.5]octane-6- carboxylate 368

N-[[6-(3-cyclopropyl-1H- pyrazole-5-carbonyl)-6- azaspiro[2.5]octan-2-yl)methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 369

N-[[6-(4-isoxazol-5-yl-1-methyl- pyrazole-3-carbonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 370

N-[[6-(2,4-dimethyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl)methyl]-1H-pyrrolo[3,2- c]pyridine-2-carboxamide 371

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 372

N-[[6-[4-(4-methylpiperazine-1- carbonyl)benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 373

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 375

(3-methyltetrahydrofuran-3-yl) 2-[(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 376

(2-hydroxy-2-methyl-propyl)2- [(1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 377

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 378

N-[[6-(2,2- dimethylpropylsulfonyl)-6- azaspiro[2.5]octan-2- yl]methyl]furo[2,3-c]pyridine-2- carboxamide 379

N-[[6-(2,2- dimethylpropylsulfonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 381

N-[[6-(2,2- dimethylpropylsulfonyl)-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 382

N-[[6-(4,4,4-trifluorobutanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 383

tert-butyl 2-[(pyrazolo[1,5- b]pyridazine-5- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 384

N-[[6-(2,4-dimethyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]furo[2,3-c]pyridine- 2-carboxamide (single isomer) 385

N-[[6-(2,4-dimethyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl)furo[2,3-c]pyridine- 2-carboxamide 387

N-[[6-[2-(2-hydroxy-2-methyl- propoxy)acetyl]-6- azaspiro[2.5]octan-2-yl)methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 388

N-[[6-[2-methyl-4- (trifluoromethyl)thiazole-5- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 389

N-[[6-(2,2- dimethylcyclopropanecarbonyl)- 6-azaspiro[2.5]octan-2- yl)methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 392

tert-butyl 2-[(imidazo[1,2- a]pyridin-6- ylmethylcarbamoylamino)methyl]- 6-azaspiro[2.5]octane-6- carboxylate 393

N-[[6-[2-(2-hydroxy-2-methyl- propoxy)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 394

N-[[6-[2-(6-amino-3- pyridyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 395

N-[[6-(morpholine-4-carbonyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 396

N-[[6-[5-(trifluoromethyl)-1H- pyrazole-3-carbonyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 397

N-[[6-(4-hydroxy-4-methyl- pentanoyl)-6-azaspiro[2.5]octan- 2-yl(methyl]-1H-pyrrolo[3,2- c|pyridine-2-carboxamide 398

N-[[6-[4- (trifluoromethyl)pyridine-3- carbonyl]-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 399

N-[[6-[2-(4- methyltetrahydropyran-4- yl)acetyl]-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 400

N-[[6-[2-(3-hydroxy-3-methyl- cyclobutyl)acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1H-pyrrolo[3,2-c]pyridine-2- carboxamide 401

(2-hydroxy-2-methyl-propyl)2- [(1H-pyrrolo[3,2-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 402

tert-butyl 2-[(imidazo[1,2- b]pyridazine-6- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 403

N-[[6-[2-[4-methyl-1-(2,2,2- trifluoroethyl)-4- piperidyl]acetyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo(3,4- c]pyridine-2-carboxamide 404

N-[[6-(2,4-dimethylthiazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 405

N-[[6-[4-(1-methyl-4- piperidyl)benzoyl]-6- azaspiro[2.5]octan-2-yl]methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 406

tert-butyl 2-[[(6-amino-1,3- dihydropyrrolo[3,4-c)pyridine-2- carbonyl)amino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 407

N-[[6-(2-pyrimidin-5-ylacetyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 408

1,1,3,3-tetradeuterio-N-[[6-(3- methylbutanoyl)-6- azaspiro[2.5]octan-2- yl]methyl]pyrrolo[3,4- c)pyridine-2-carboxamide 409

(3-methyloxetan-3-yl)2- [[(1,1,3,3- tetradeuteriopyrrolo[3,4- c]pyridine-2- carbonyl)amino]methyl]-6- azaspiro[2.5]octane-6- carboxylate 410

1,1,3,3-tetradeuterio-N-[[6-(2,4- dimethyloxazole-5-carbonyl)-6- azaspiro[2.5]octan-2- yl]methyl]pyrrolo[3,4- clpyridine-2-carboxamide 411

N-[(6-benzoyl-6- azaspiro[2.5]octan-2- yl)methyl]furol2,3-c]pyridine-2 carboxamide 413

N-[[(2S)-6-(3-methylbutanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 414

N-[[(2R)-6-(3-methylbutanoyl)- 6-azaspiro[2.5]octan-2- yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2 carboxamide 415

N-[[6-(4-methyloxazole-5- carbonyl)-6-azaspiro[2.5]octan- 2-yl]methyl]-1,3- dihydropyrrolo[3,4-c]pyridine-2- carboxamide 416

isopropyl 2-[(furo[2,3- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 417

(3-methyloxetan-3-yl)2- [(furo[2,3-c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate 418

N-[(6-benzoyl-6- azaspiro[2.5]octan-2-yl)methyl]- 1,3-dihydropyrrolo[3,4- c]pyridine-2-carboxamide 419

(3-methyloxetan-3-yl) (2S)-2- (1,3-dihydropyrrolo[3,4- c]pyridine-2- carbonylamino)methyl]-6- azaspiro[2.5]octane-6- carboxylate

or a pharmaceutically acceptable salt thereof, or a stereoisomer or a pharmaceutically acceptable salt of said stereoisomer.

Pharmaceutical Description

The dosage forms of the present invention may contain a mixture of one or more compounds of this invention, and may include additional materials known to those skilled in the art as pharmaceutical excipients. “Excipient” includes any excipient commonly used in pharmaceutics and should be selected on the basis of compatibility and the release profile properties of the desired dosage form. Exemplary excipients include, e.g., binders, suspending agents, disintegration agents, filling agents, surfactants, solubilizers, stabilizers, lubricants, wetting agents, diluents, and the like. Exemplary exipients include, e.g., acacia, gelatin, colloidal silicon dioxide, calcium glycerophosphate, calcium lactate, maltodextrin, glycerine, magnesium silicate, sodium caseinate, soy lecithin, sodium chloride, tricalcium phosphate, dipotassium phosphate, sodium stearoyl lactylate, carrageenan, monoglyceride, diglyceride, pregelatinized starch, and the like. See, e.g., Hoover, John E., Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa. 1975.

Exemplary excipients include: stabilizing additives such as gum acacia, gelatin, methyl cellulose, polyethylene glycol, carboxylic acids and salts thereof, and polylysine; acidifying agents (acetic acid, glacial acetic acid, citric acid, fumaric acid, hydrochloric acid, diluted hydrochloric acid, malic acid, nitric acid, phosphoric acid, diluted phosphoric acid, sulfuric acid, tartaric acid); aerosol propellants (butane, dichlorodifluoro-methane, dichlorotetrafluoroethane, isobutane, propane, trichloromonofluoromethane); air displacements (carbon dioxide, nitrogen); alcohol denaturants (denatonium benzoate, methyl isobutyl ketone, sucrose octacetate); alkalizing agents (strong ammonia solution, ammonium carbonate, diethanolamine, diisopropanolamine, potassium hydroxide, sodium bicarbonate, sodium borate, sodium carbonate, sodium hydroxide, trolamine); anticaking agents (see “glidant” below); antifoaming agents (dimethicone, simethicone); antimicrobial preservatives (benzalkonium chloride, benzalkonium chloride solution, benzelthonium chloride, benzoic acid, benzyl alcohol, butylparaben, cetylpyridinium chloride, chlorobutanol, chlorocresol, cresol, dehydroacetic acid, ethylparaben, methylparaben, methylparaben sodium, phenol, phenylethyl alcohol, phenylmercuric acetate, phenylmercuric nitrate, potassium benzoate, potassium sorbate, propylparaben, propylparaben sodium, sodium benzoate, sodium dehydroacetate, sodium propionate, sorbic acid, thimerosal, thymol); antioxidants (ascorbic acid, acorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, hypophosphorous acid, monothioglycerol, propyl gallate, sodium formaldehyde sulfoxylate, sodium metabisulfite, sodium thiosulfate, sulfur dioxide, tocopherol, tocopherols excipient); buffering agents (acetic acid, ammonium carbonate, ammonium phosphate, boric acid, citric acid, lactic acid, phosphoric acid, potassium citrate, potassium metaphosphate, potassium phosphate monobasic, sodium acetate, sodium citrate, sodium lactate solution, dibasic sodium phosphate, monobasic sodium phosphate); capsule lubricants (see “tablet and capsule lubricant” below); chelating agents (edetate disodium, ethylenediaminetetraacetic acid and salts, edetic acid); coating agents (sodium carboxymethylcellulose, cellulose acetate, cellulose acetate phthalate, ethylcellulose, gelatin, pharmaceutical glaze, hydroxypropyl cellulose, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose phthalate, methacrylic acid copolymer, methylcellulose, polyethylene glycol, polyvinyl acetate phthalate, shellac, sucrose, titanium dioxide, carnauba wax, microcystalline wax, zein); colorants (caramel, red, yellow, black or blends, ferric oxide); complexing agents (ethylenediaminetetraacetic acid and salts (EDTA), edetic acid, gentisic acid ethanolmaide, oxyquinoline sulfate); desiccants (calcium chloride, calcium sulfate, silicon dioxide); emulsifying and/or solubilizing agents (acacia, cholesterol, diethanolamine (adjunct), glyceryl monostearate, lanolin alcohols, lecithin, mono- and di-glycerides, monoethanolamine (adjunct), oleic acid (adjunct), oleyl alcohol (stabilizer), poloxamer, polyoxyethylene 50 stearate, polyoxyl 35 caster oil, polyoxyl 40 hydrogenated castor oil, polyoxyl 10 oleyl ether, polyoxyl 20 cetostearyl ether, polyoxyl 40 stearate, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, propylene glycol diacetate, propylene glycol monostearate, sodium lauryl sulfate, sodium stearate, sorbitan monolaurate, soritan monooleate, sorbitan monopalmitate, sorbitan monostearate, stearic acid, trolamine, emulsifying wax); filtering aids (powdered cellulose, purified siliceous earth); flavors and perfumes (anethole, benzaldehyde, ethyl vanillin, menthol, methyl salicylate, monosodium glutamate, orange flower oil, peppermint, peppermint oil, peppermint spirit, rose oil, stronger rose water, thymol, tolu balsam tincture, vanilla, vanilla tincture, vanillin); glidants and/or anticaking agents (calcium silicate, magnesium silicate, colloidal silicon dioxide, talc); humectants (glycerin, hexylene glycol, propylene glycol, sorbitol); plasticizers (castor oil, diacetylated monoglycerides, diethyl phthalate, glycerin, mono- and di-acetylated monoglycerides, polyethylene glycol, propylene glycol, triacetin, triethyl citrate); polymers (e.g., cellulose acetate, alkyl celloloses, hydroxyalkylcelloloses, acrylic polymers and copolymers); solvents (acetone, alcohol, diluted alcohol, amylene hydrate, benzyl benzoate, butyl alcohol, carbon tetrachloride, chloroform, corn oil, cottonseed oil, ethyl acetate, glycerin, hexylene glycol, isopropyl alcohol, methyl alcohol, methylene chloride, methyl isobutyl ketone, mineral oil, peanut oil, polyethylene glycol, propylene carbonate, propylene glycol, sesame oil, water for injection, sterile water for injection, sterile water for irrigation, purified water); sorbents (powdered cellulose, charcoal, purified siliceous earth); carbon dioxide sorbents (barium hydroxide lime, soda lime): stiffening agents (hydrogenated castor oil, cetostearyl alcohol, cetyl alcohol, cetyl esters wax, hard fat, paraffin, polyethylene excipient, stearyl alcohol, emulsifying wax, white wax, yellow wax); suspending and/or viscosity-increasing agents (acacia, agar, alginic acid, aluminum monostearate, bentonite, purified bentonite, magma bentonite, carbomer 934p, carboxymethylcellulose calcium, carboxymethylcellulose sodium, carboxymethycellulose sodium 12, carrageenan, microcrystalline and carboxymethylcellulose sodium cellulose, dextrin, gelatin, guar gum, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, magnesium aluminum silicate, methylcellulose, pectin, polyethylene oxide, polyvinyl alcohol, povidone, propylene glycol alginate, silicon dioxide, colloidal silicon dioxide, sodium alginate, tragacanth, xanthan gum); sweetening agents (aspartame, dextrates, dextrose, excipient dextrose, fructose, mannitol, saccharin, calcium saccharin, sodium saccharin, sorbitol, solution sorbitol, sucrose, compressible sugar, confectioner's sugar, syrup); tablet binders (acacia, alginic acid, sodium carboxymethylcellulose, microcrystalline cellulose, dextrin, ethylcellulose, gelatin, liquid glucose, guar gum, hydroxypropyl methylcellulose, methycellulose, polyethylene oxide, povidone, pregelatinized starch, syrup); tablet and/or capsule diluents (calcium carbonate, dibasic calcium phosphate, tribasic calcium phosphate, calcium sulfate, microcrystalline cellulose, powdered cellulose, dextrates, dextrin, dextrose excipient, fructose, kaolin, lactose, mannitol, sorbitol, starch, pregelatinized starch, sucrose, compressible sugar, confectioner's sugar); tablet disintegrants (alginic acid, microcrystalline cellulose, croscarmellose sodium, corspovidone, polacrilin potassium, sodium starch glycolate, starch, pregelatinized starch); tablet and/or capsule lubricants (calcium stearate, glyceryl behenate, magnesium stearate, light mineral oil, polyethylene glycol, sodium stearyl fumarate, stearic acid, purified stearic acid, talc, hydrogenated vegetable oil, zinc stearate); tonicity agent (dextrose, glycerin, mannitol, potassium chloride, sodium chloride); vehicle: flavored and/or sweetened (aromatic elixir, compound benzaldehyde elixir, iso-alcoholic elixir, peppermint water, sorbitol solution, syrup, tolu balsam syrup); vehicle: oleaginous (almond oil, corn oil, cottonseed oil, ethyl oleate, isopropyl myristate, isopropyl palmitate, mineral oil, light mineral oil, myristyl alcohol, octyldodecanol, olive oil, peanut oil, persic oil, seame oil, soybean oil, squalane); vehicle: solid carrier (sugar spheres): vehicle: sterile (bacteriostatic water for injection, bacteriostatic sodium chloride injection); viscosity-increasing (see “suspending agent” below); water repelling agent (cyclomethicone, dimethicone, simethicone); and wetting and/or solubilizing agent (benzalkonium chloride, benzethonium chloride, cetylpyridinium chloride, docusate sodium, nonoxynol 9, nonoxynol 10, octoxynol 9, poloxamer, polyoxyl 35 castor oil, polyoxyl 40, hydrogenated castor oil, polyoxyl 50 stearate, polyoxyl 10 oleyl ether, polyoxyl 20, cetostearyl ether, polyoxyl 40 stearate, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, sodium lauryl sulfate, sorbitan monolaureate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, tyloxapol). This list is not meant to be exclusive, but instead merely representative of the classes of excipients and the particular excipients which may be used in dosage forms of the present invention.

In certain aspects, the invention relates to methods of treating diseases or conditions mediated by elevated levels of NAMPT, or which are generally mediated by NAMPT activity. Such disease or condition can be one or more selected from the group consisting of cancer, ovarian cancer, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, bladder cancer, pancreatic cancer, leukemia, lymphoma, Hodgkin's disease, viral infections, Human Immunodeficiency Virus, hepatitis virus, herpes virus, herpes simplex, inflammatory disorders, irritable bowel syndrome, inflammatory bowel disease, rheumatoid arthritis, asthma, chronic obstructive pulmonary disease, osteoarthritis, osteoporosis, dermatitis, atoptic dermatitis, psoriasis, systemic lupus erythematosis, multiple sclerosis, psoriatic arthritis, ankylosing spodylitis, graft-versus-host disease, Alzheimer's disease, cerebrovascular accident, atherosclerosis, diabetes, glomerulonephiritis, metabolic syndrome, non-small cell lung cancer, small cell lung cancer, multiple myeloma, leukemias, lymphomas, squamous cell cancers, kidney cancer, uretral and bladder cancers, cancers of head and neck, and cancers of the brain and central nervous system (CNS).

The inventive compounds can be useful in the therapy of proliferative diseases such as, but not limited to cancer, autoimmune diseases, viral diseases, fungal diseases, neurological/neurodegenerative disorders, arthritis, inflammation, anti-proliferative (e.g., ocular retinopathy), neuronal, alopecia and cardiovascular disease.

More specifically, the compounds can be useful in the treatment of a variety of cancers, including (but not limited to) the following: carcinoma, including that of the bladder, breast, colon, kidney, liver, lung, including small cell lung cancer, non-small cell lung cancer, head and neck, esophagus, gall bladder, ovary, pancreas, stomach, cervix, thyroid, prostate, and skin, including squamous cell carcinoma, hematopoietic tumors of lymphoid lineage, including leukemia, acute lymphocytic leukemia, acute lymphoblastic leukemia, B-cell lymphoma, T-cell lymphoma, Hodgkins lymphoma, non-Hodgkins lymphoma, hairy cell lymphoma, mantle cell lymphoma, myeloma, and Burkett's lymphoma, hematopoietic tumors of myeloid lineage, including acute and chronic myelogenous leukemias, myelodysplastic syndrome and promyelocytic leukemia, tumors of mesenchymal origin, including fibrosarcoma and rhabdomyosarcoma, tumors of the central and peripheral nervous system, including astrocytoma, neuroblastoma, glioma and schwannomas, and other tumors, including melanoma, seminoma, teratocarcinoma, osteosarcoma, xenoderoma pigmentosum, keratoctanthoma, thyroid follicular cancer and Kaposi's sarcoma.

The compounds of the invention may induce or inhibit apoptosis.

The compounds of the invention may also be useful in the chemoprevention of cancer. Chemoprevention is defined as inhibiting the development of invasive cancer by either blocking the initiating mutagenic event or by blocking the progression of pre-malignant cells that have already suffered an insult or inhibiting tumor relapse.

A further aspect of the invention is a method of inhibiting a NAMPT pathway in a subject, said method comprising administering to said subject a pharmaceutically acceptable amount of a compound of the invention to a subject in need thereof

Another embodiment of the invention comprises a pharmaceutical formulation of the invention, wherein the pharmaceutical formulation, upon administration to a human, results in a decrease in tumor burden.

Still another embodiment of the invention is a pharmaceutical formulation comprising at least one compound of Formula I and a pharmaceutically acceptable excipient. Such formulations may further comprise one or more adjunctive active agent. The pharmaceutical formulations of the invention may further comprise a therapeutic effective amount of an adjunctive active agent.

The compounds of the present invention are also useful in combination therapies with at least one adjunctive active agent. Such methods include regimes in which the compound of the invention and the at least one adjunctive active agent are administered simultaneously or sequentially. Also useful are pharmaceutical compositions in which at least one compound of the present invention and at least one adjunctive active agent are combined in a single formulation.

The expression “adjunctive active agent” generally refers to agents which targets the same or a different disease, symptom, or medical condition as the primary therapeutic agent. Adjunctive active agents may treat, alleviate, relieve, or ameliorate side effects caused by administration of the primary therapeutic agents. Examples of adjunctive active agents include, but are not limited to, antineoplastic agents, filgrastim, and erythropoietin. Such agents include those which modify blood cell growth and maturation. Non-limiting examples of adjunctive active agent are filgrastim, pegfilgrastim and erythropoietin. Other such adjunctive active agents include those which inhibit nausea associated with administration of chemotherapeutic agents, such as a 5-HT₃ receptor inhibitor (e.g., dolansetron, granisetron, or ondansetron), with or without dexamethasone. The invention also describes one or more uses of the compounds of the present invention with an adjunctive active agent such as TNF, GCSF, or other chemotherapeutic agents. Additional adjunctive active agents include those that mediate cytotoxicity of NAMPT inhibitors, such as nicotinic acid rescue agents, or other compounds that play a role in the NAMPT pathway, such as niacin (nicotinic acid), nicotinamide, or related compounds, or modified release formulations of such compounds, for example, NIASPAN®.

The terms “chemotherapeutic agent” and “antineoplastic agent” generally refer to agents, which treat, prevent, cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve, or affect malignancies and their metastasis. Examples of such agents include, but are not limited to, prednisone, fluorouracil (e.g., 5-fluorouracil (5-FU)), anastrozole, bicalutamide, carboplatin, cisplatin, chlorambucil, cisplatin, carboplatin, docetaxel, doxorubicin, flutamide, interferon-alpha, letrozole, leuprolide, megestrol, mitomycin, oxaliplatin, paclitaxel, plicamycin (Mithracin™), tamoxifen, thiotepa, topotecan, valrubicin, vinblastine, vincristine, and any combination of any of the foregoing.

The invention is also directed to a method of treating or preventing a disorder associated with excessive rate of growth of cells in a mammal comprising administering to the mammal an effective amount of the pharmaceutical formulation of the invention. Non-limiting examples of disorder include cancer or metastasis from malignant tumors.

Another aspect of the invention is a method of inhibiting tumor cell growth and rate of division in a mammal with cancer, or other disorder associated with abnormally dividing cells comprising administering to the mammal an effective amount of the pharmaceutical formulation of this invention.

Another embodiment of the invention is a method of treating bone pain due to excessive growth of a tumor or metastasis to bone in a mammal in need thereof comprising administering to the mammal an effective amount of the pharmaceutical formulation of this invention.

A further embodiment of the invention is a method of preparing a pharmaceutical formulation comprising mixing at least one compound of the present invention, and, optionally, one or more pharmaceutically acceptable excipients.

The invention is also directed to methods of synthesizing compounds of the present invention.

Still another aspect of this invention is to provide a method for treating, preventing, inhibiting or eliminating a disease or condition in a patient by inhibiting NAMPT in said patient by administering a therapeutically effective amount of at least one compound of this disclosure, wherein said disease or condition is selected from the group consisting of cancer, ovarian cancer, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, bladder cancer, pancreatic cancer, leukemia, lymphoma, Hodgkin's disease, viral infections, Human Immunodeficiency Virus, hepatitis virus, herpes virus, herpes simplex, inflammatory disorders, irritable bowel syndrome, inflammatory bowel disease, rheumatoid arthritis, asthma, chronic obstructive pulmonary disease, osteoarthritis, osteoporosis, dermatitis, atoptic dermatitis, psoriasis, systemic lupus erythematosis, multiple sclerosis, psoriatic arthritis, ankylosing spodylitis, graft-versus-host disease, Alzheimer's disease, cerebrovascular accident, atherosclerosis, diabetes, glomerulonephiritis, metabolic syndrome, non-small cell lung cancer, small cell lung cancer, multiple myeloma, leukemias, lymphomas, squamous cell cancers, kidney cancer, uretral and bladder cancers, cancers of head and neck, cancers of the brain and central nervous system.

In a certain embodiment, the compounds of Formula I can be used in the treatment of solid and liquid tumors, non-small cell lung cancer, leukemia, lymphoma, ovarian cancer, glioma, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, rhino-gastric tumors, colorectal cancer, CNS cancer, bladder cancer, pancreatic cancer and Hodgkin's disease.

In a certain embodiment, the compounds of Formula I can be used in the treatment of solid and liquid tumors, non-small cell lung cancer, leukemia, lymphoma, ovarian cancer, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, rhino-gastric tumors, colorectal cancer, bladder cancer, pancreatic cancer and Hodgkin's disease.

Another embodiment is a pharmaceutical formulation comprising a pharmaceutically acceptable compound of the present invention, which provides, upon administration to a subject (e.g., a human), a decrease in tumor burden and/or metastases. The pharmaceutical formulation can be administered by oral means or other suitable means.

Yet another embodiment is a method of treating ovarian cancer in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating non-small cell lung cancer (NSCLC) in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating colon cancer in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating breast cancer in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating leukemia in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating colon cancer before or after surgical resection and/or radiation therapy, in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of treating cancer before or after surgical resection and/or radiation therapy, in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention, including adjunctive therapy to treat nausea, with or without dexamethasone.

Yet another embodiment is a method of treating cancer before or after surgical resection and or radiation therapy, in a subject (e.g., a human) in need thereof by administering to the subject an effective amount of the compound or the pharmaceutical formulation of the present invention, including adjunctive therapy with one or more additional therapeutic agents, or their pharmaceutically acceptable salts. Non-limiting examples of such additional therapeutic agents include cytotoxic agents (such as for example, but not limited to, DNA interactive agents (such as cisplatin or doxorubicin)); taxanes (e.g. taxotere, taxol); topoisomerase II inhibitors (such as etoposide); topoisomerase I inhibitors (such as irinotecan (or CPT-11), camptostar, or topotecan); tubulin interacting agents (such as paclitaxel, docetaxel or the epothilones); hormonal agents (such as tamoxifen); thymidilate synthase inhibitors (such as 5-fluorouracil or 5-FU); anti-metabolites (such as methoxtrexate); alkylating agents (such as temozolomide, cyclophosphamide); Farnesyl protein transferase inhibitors (such as, SARASAR™. (4-[2-[4-[(11R)-3,10-dibromo-8-chloro-6,11-dihydro-5H-benzo[5,-6]cyclohepta[1,2-b]pyridin-11-yl-]-1-piperidinyl]-2-oxoehtyl]-1-piperidine-carboxamide, or SCH 66336), tipifarnib (Zarnestra® or R115777 from Janssen Pharmaceuticals), L778,123 (a farnesyl protein transferase inhibitor from Merck & Company, Whitehouse Station, N.J.), BMS 214662 (a farnesyl protein transferase inhibitor from Bristol-Myers Squibb Pharmaceuticals, Princeton, N.J.); signal transduction inhibitors (such as, Iressa® (from Astra Zeneca Pharmaceuticals, England), Tarceva® (EGFR kinase inhibitors), antibodies to EGFR (e.g., C225), GLEEVEC® (C-abl kinase inhibitor from Novartis Pharmaceuticals, East Hanover, N.J.); interferons such as, for example, Intron® (from Merck & Company), Peg-Intron® (from Merck & Company); hormonal therapy combinations; aromatase combinations; ara-C, adriamycin, cytoxan, and gemcitabine.

Other anti-cancer (also known as anti-neoplastic) agents include but are not limited to Uracil mustard, Chlormethine, Ifosfamide, Melphalan, Chlorambucil, Pipobroman, Triethylenemelamine, Triethylenethiophosphoramine, Busulfan, Carmustine, Lomustine, Streptozocin, Dacarbazine, Floxuridine, Cytarabine, 6-Mercaptopurine, 6-Thioguanine, Fludarabine phosphate, oxaliplatin, leucovirin, oxaliplatin (ELOXATIN® from Sanofi-Synthelabo Pharmaceuticals, France), Pentostatine, Vinblastine, Vincristine, Vindesine, Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Mithramycin, Deoxycoformycin, Mitomycin-C, L-Asparaginase, Teniposide 17α-Ethinylestradiol, Diethylstilbestrol, Testosterone, Prednisone, Fluoxymesterone, Dromostanolone propionate, Testolactone, Megestrolacetate, Methylprednisolone, Methyltestosterone, Prednisolone, Triamcinolone, Chlorotrianisene, Hydroxyprogesterone, Aminoglutethimide, Estramustine, Medroxyprogesteroneacetate, Leuprolide, Flutamide, Toremifene, goserelin, Cisplatin, Carboplatin, Hydroxyurea, Amsacrine, Procarbazine, Mitotane, Mitoxantrone, Levamisole, Navelbene, Anastrazole, Letrazole, Capecitabine, Reloxafine, Droloxafine, Hexamethylmelamine, Avastin, herceptin, Bexxar, Velcade®, Zevalin, Trisenox, Xeloda, Vinorelbine, Porfimer, Erbitux, Liposomal, Thiotepa, Altretamine, Melphalan, Trastuzumab, Lerozole, Fulvestrant, Exemestane, Ifosfomide, Rituximab, C225, and Campath, 5-fluorouracil and leucovorin, with or without a 5-HT₃ receptor inhibitor (e.g., dolansetron, granisetron, ondansetron) with or without dexamethasone.

Additionally, according to the present invention, the compounds of the invention described herein may be administered and/or formulated in combination with an adjunctive active agent. In certain embodiments, the adjunctive active agent is niacin, nicotinamide, nicotinic acid, nicotinamide mononucleotide (NMN), or variations thereof, including modified release formulations of niacin, such as NIASPAN®. Niacin, nicotinamide, nicotinic acid, nicotinamide mononucleotide (NMN), or variations thereof have also been described in the literature as “rescue agents” or “rescuing agents” and these terms have been used herein. The role of nicotinamide and/or nicotinic acid as a rescuing or rescue agent has for example been described by Beauparlant et al. in Anti-Cancer Drugs 2009, 20:346-354 and by Rongvaux et al. in The Journal of Immunology, 2008, 181: 4685-4695. These two references describe the role of a rescuing or rescue agent with regards to ameliorating possible toxic effects of NAMPT inhibitors.

If formulated as a fixed dose, such combination products employ the compounds of this invention within the dosage range described herein (or as known to those skilled in the art) and the other pharmaceutically active agents or treatments within its dosage range. For example, the CDC2 inhibitor olomucine has been found to act synergistically with known cytotoxic agents in inducing apoptosis (J. Cell Sci., (1995) 108, 2897). The compounds of the invention may also be administered sequentially with known anticancer or cytotoxic agents when a combination formulation is inappropriate. In any combination treatment, the invention is not limited in the sequence of administration; compounds of the disclosed Formulas may be administered either prior to or after administration of the known anticancer or cytotoxic agent. For example, the cytotoxic activity of the cyclin-dependent kinase inhibitor flavopiridol is affected by the sequence of administration with anticancer agents. Cancer Research, (1997) 57, 3375. Such techniques are within the skills of persons skilled in the art as well as attending physicians.

Any of the aforementioned methods may be augmented by administration of fluids (such as water), loop diuretics, one or more adjunctive active agents, such as a chemotherapeutic or antineoplastic agent, such as leucovorin and fluorouracil, or an adjunctive chemotherapeutic agent (such as filgrastim and erythropoietin), or any combination of the foregoing.

Yet another embodiment is a method for administering a compound of the instant invention to a subject (e.g., a human) in need thereof by administering to the subject the pharmaceutical formulation of the present invention.

Yet another embodiment is a method of preparing a pharmaceutical formulation of the present invention by mixing at least one pharmaceutically acceptable compound of the present invention, and, optionally, one or more pharmaceutically acceptable additives or excipients.

For preparing pharmaceutical compositions from the compounds described by this invention, inert, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets and suppositories. The powders and tablets may be comprised of from about 5 to about 95 percent active ingredient. Suitable solid carriers are known in the art, e.g., magnesium carbonate, magnesium stearate, talc, sugar or lactose. Tablets, powders, cachets and capsules can be used as solid dosage forms suitable for oral administration. Examples of pharmaceutically acceptable carriers and methods of manufacture for various compositions may be found in A. Gennaro (ed.), Remington's Pharmaceutical Sciences, 18th Edition, (1990), Mack Publishing Co., Easton, Pa.

The compositions and formulations of the invention can be administered as sterile compositions and sterile formulations. Sterile pharmaceutical formulations are compounded or manufactured according to pharmaceutical-grade sterilization standards (e.g., United States Pharmacopeia Chapters 797, 1072, and 1211; California Business & Professions Code 4127.7; 16 California Code of Regulations 1751, 21 Code of Federal Regulations 21, or ex-U.S. counterparts to such regulations) known to those of skill in the art.

Liquid form preparations include solutions, suspensions and emulsions. As an example may be mentioned water or water-propylene glycol solutions for parenteral injection or addition of sweeteners and opacifiers for oral solutions, suspensions and emulsions. Liquid form preparations may also include solutions for intranasal administration.

Aerosol preparations suitable for inhalation may include solutions and solids in powder form, which may be in combination with a pharmaceutically acceptable carrier, such as an inert compressed gas, e.g. nitrogen.

Also included are solid form preparations that are intended to be converted, shortly before use, to liquid form preparations for either oral or parenteral administration. Such liquid forms include solutions, suspensions and emulsions.

The compounds of the invention may also be deliverable transdermally. The transdermal compositions can take the form of creams, lotions, aerosols and/or emulsions and can be included in a transdermal patch of the matrix or reservoir type as are conventional in the art for this purpose.

The compounds of this invention may also be delivered subcutaneously.

The compound can be administered orally or intravenously.

The pharmaceutical preparation can be in a unit dosage form. In such form, the preparation is subdivided into suitably sized unit doses containing appropriate quantities of the active component, e.g., an effective amount to achieve the desired purpose.

The quantity of active compound in a unit dose of preparation may be varied or adjusted from about 1 mg to about 1000 mg, for example from about 1 mg to about 500 mg, in particular from about 1 mg to about 250 mg, or from about 1 mg to about 25 mg, according to the particular application.

The actual dosage employed may be varied depending upon the requirements of the patient and the severity of the condition being treated. Determination or the proper dosage regimen for a particular situation is within the skill of the art. For convenience, the total daily dosage may be divided and administered in portions during the day as required.

The amount and frequency of administration of the compounds of the invention and/or the pharmaceutically acceptable salts thereof will be regulated according to the judgment of the attending clinician considering such factors as age, condition and size of the patient as well as severity of the symptoms being treated. A typical recommended daily dosage regimen for oral administration can range from about 1 mg/day to about 500 mg/day, preferably 1 mg/day to 200 mg/day, in two to four divided doses.

SCHEMES AND EXAMPLES

Exemplary, non-limiting, chemical entities and methods useful in preparing compounds of the invention will now be described by reference to illustrative synthetic schemes for their general preparation below and the specific examples that follow. Those skilled in the art will appreciate that other synthetic routes may be used to synthesize the compounds according to the invention. Although specific starting materials and reagents are depicted and discussed herein, other starting materials and reagents can be easily substituted to provide a variety of derivatives and/or reaction conditions. In addition, many of the exemplary compounds prepared by the described methods can be further modified in light of this disclosure using conventional chemistry well known to those skilled in the art.

Artisans will recognize that, to obtain the various compounds herein, starting materials may be suitably selected so that the ultimately desired substituents will be carried through the reaction scheme with or without protection as appropriate to yield the desired product. Alternatively, it may be necessary or desirable to employ, in the place of the ultimately desired substituent, a suitable group that may be carried through the reaction scheme and replaced as appropriate with the desired substituent. Each of the reactions depicted in the reaction schemes is preferably run at a temperature from about 0° C. to the reflux temperature of the solvent used. Unless otherwise specified, the variables shown in the schemes below are as defined above in reference to Formula I.

Compounds according to the invention may be synthesized by synthetic routes that include processes analogous to those well-known in the chemical arts, particularly in light of the description contained herein, and those for other heterocycles described in: Comprehensive Heterocyclic Chemistry II, Editors Katritzky and Rees, Elsevier, 1997, e.g. Volume 3; Liebigs Annalen der Chemie, (9):1910-16, (1985); Helvetica Chimica Acta, 41:1052-60, (1958); Arzneimittel-Forschung, 40(12):1328-31, (1990), each of which are expressly incorporated by reference. Starting materials are generally available from commercial sources such as Sigma-Aldrich Chemicals (Milwaukee, Wis.) or are readily prepared using methods well known to those skilled in the art (e.g., prepared by methods generally described in Louis F. Fieser and Mary Fieser, Reagents for Organic Synthesis, v. 1-23, Wiley, N.Y. (1967-2006 ed.), or Beilsteins Handbuch der organischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin, including supplements (also available via the Beilstein online database).

Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing compounds according to the invention and necessary reagents and intermediates are known in the art and include, for example, those described in R. Larock, Comprehensive Organic Transformations, VCH Publishers (1989); T W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3rd Ed., John Wiley and Sons (1999); and L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995) and subsequent editions thereof. The need for such protection will vary depending on the nature of the remote functionality and the conditions of the preparation methods. Suitable amino-protecting groups include acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and 9-fluorenylmethyleneoxycarbonyl (Fmoc) The need for such protection is readily determined by one skilled in the art.

Additional particularly useful reactions in preparing compounds of the present invention include alkylation, reductive amination, oxidation, reduction, and hydrolysis reactions. Such transformations are well within the ordinary skill in the art.

Compounds according to the invention may be prepared singly or as compound libraries comprising, for example, at least two, or 5 to 1,000 compounds, or 10 to 100 compounds. Libraries of compounds of Formula I may be prepared by a combinatorial “split and mix” approach or by multiple parallel syntheses using either solution phase or solid phase chemistry, by procedures known to those skilled in the art. Thus, according to a further aspect of the invention there is provided a compound library comprising at least two compounds of Formula I, or pharmaceutically acceptable salts thereof.

In the methods of preparing compounds according to the invention, it may be advantageous to separate reaction products from one another and/or from starting materials. The desired products of each step or series of steps is separated and/or purified to the desired degree of homogeneity by the techniques common in the art. Typically such separations involve multiphase extraction, crystallization from a solvent or solvent mixture, distillation, sublimation, or chromatography. Chromatography can involve any number of methods including, for example: reverse-phase and normal phase; size exclusion; ion exchange; high, medium and low pressure liquid chromatography methods and apparatus; small scale analytical; simulated moving bed (SMB) and preparative thin or thick layer chromatography, as well as techniques of small scale thin layer and flash chromatography.

Another class of separation methods involves treatment of a mixture with a reagent selected to bind to or render otherwise separable a desired product, unreacted starting material, reaction by product, or the like. Such reagents include adsorbents or absorbents such as activated carbon, molecular sieves, ion exchange media, or the like. Alternatively, the reagents can be acids in the case of a basic material, bases in the case of an acidic material, binding reagents such as antibodies, binding proteins, selective chelators such as crown ethers, liquid/liquid ion extraction reagents (LIX), or the like. Selection of appropriate methods of separation depends on the nature of the materials involved, such as, boiling point and molecular weight in distillation and sublimation, presence or absence of polar functional groups in chromatography, stability of materials in acidic and basic media in multiphase extraction, and the like.

A single stereoisomer, e.g., an enantiomer, substantially free of its stereoisomer may be obtained by resolution of the racemic mixture using a method such as formation of diastereomers using optically active resolving agents (Eliel, E. and Wilen, S. “Stereochemistry of Organic Compounds,” John Wiley & Sons, Inc., New York, 1994; Lochmuller, C. H., (1975) J. Chromatogr., 113(3):283-302). Racemic mixtures of chiral compounds of the invention can be separated and isolated by any suitable method, including: (1) formation of ionic, diastereomeric salts with chiral compounds and separation by fractional crystallization or other methods, (2) formation of diastereomeric compounds with chiral derivatizing reagents, separation of the diastereomers, and conversion to the pure stereoisomers, and (3) separation of the substantially pure or enriched stereoisomers directly under chiral conditions. See: “Drug Stereochemistry, Analytical Methods and Pharmacology,” Irving W. Wainer, Ed Marcel Dekker, Inc., New York (1993).

Under method (1), diastereomeric salts can be formed by reaction of enantiomerically pure chiral bases such as brucine, quinine, ephedrine, strychnine, a-methyl-b-phenylethylamine (amphetamine), and the like with asymmetric compounds bearing acidic functionality, such as carboxylic acid and sulfonic acid. The diastereomeric salts may be induced to separate by fractional crystallization or ionic chromatography. For separation of the optical isomers of amino compounds, addition of chiral carboxylic or sulfonic acids, such as camphorsulfonic acid, tartaric acid, mandelic acid, or lactic acid can result in formation of the diastereomeric salts.

Alternatively, by method (2), the substrate to be resolved is reacted with one enantiomer of a chiral compound to form a diastereomeric pair (E, and Wilen, S. “Stereochemistry of Organic Compounds”, John Wiley & Sons, Inc., 1994, p. 322). Diastereomeric compounds can be formed by reacting asymmetric compounds with enantiomerically pure chiral derivatizing reagents, such as menthyl derivatives, followed by separation of the diastereomers and hydrolysis to yield the pure or enriched enantiomer. A method of determining optical purity involves making chiral esters, such as a menthyl ester, e.g., (−) menthyl chloroformate in the presence of base, or Mosher ester, a-methoxy-a-(trifluoromethyl)phenyl acetate of the racemic mixture and analyzing the 1H NMR spectrum for the presence of the two atropisomeric enantiomers or diastereomers (Jacob III. J. Org. Chem. (1982) 47:4165). Stable diastereomers of atropisomeric compounds can be separated and isolated by normal- and reverse-phase chromatography following methods for separation of atropisomeric naphthyl-isoquinolines (WO 96/15111). By method (3), a racemic mixture of two enantiomers can be separated by chromatography using a chiral stationary phase (“Chiral Liquid Chromatography” (1989) W. J. Lough, Ed., Chapman and Hall, New York; Okamoto, J. Chromatogr., (1990) 513:375-378). Enriched or purified enantiomers can be distinguished by methods used to distinguish other chiral molecules with asymmetric carbon atoms, such as optical rotation and circular dichroism.

Abbreviations and acronyms used in the following Schemes and elsewhere herein are defined as follows:

-   -   CDCl₃ deuterated chloroform     -   CD₃OD deuterated methanol     -   δ chemical shift (ppm)     -   DCM Dichloromethane     -   DIPEA Diisopropylethylamine     -   DMF N,N-dimethylformamide     -   DMSO Dimethyl sulfoxide     -   EDCI 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide     -   ELSD Evaporative light scattering detector     -   equiv Molar equivalent     -   ESI Electrospray ionization     -   h Hour(s)     -   H₂ Hydrogen gas         O-(7-Azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium     -   HATU hexafluorophosphate     -   ¹H NMR proton nuclear magnetic resonance spectroscopy     -   HOBt 1-Hydroxybenzotriazole     -   HPLC High performance liquid chromatography     -   LC/MS Liquid chromatography—mass spectrometry     -   MeOH Methanol     -   MHz megahertz     -   min Minute(s)     -   PDA Photo diode array detector     -   psi Pounds per square inch     -   rt Room temperature     -   Raney-Ni Raney Nickel     -   R^(f) Retention factor     -   TFA Trifluoroacetic acid     -   Tf₂O Trifluoromethanesulfonic anhydride     -   THF Tetrahydrofuran     -   TLC Thin layer chromatography

Exemplary general reaction schemes that are useful in preparing compounds of the invention are described below.

Compounds of Formula I may be prepared as shown above in Scheme A. Compounds of Formula A, in which X is, for example, OH, chloro, or bromo, are reacted with amines B to produce compounds of Formula I. Where X is OH, coupling reactions may occur in the presence of a coupling reagent such as EDCI, HATU, or HOBt, and a base (e.g., K₂CO₃, Cs₂CO₃, trialkylamine, sodium or potassium alkoxide) in an inert solvent such as dichloromethane, N,N-dialkylformamide, N,N-dialkylacetamide, dialkylethers, cyclic ethers, DMSO, or N-methyl-2-pyrrolidinone, or a mixture thereof, at temperatures ranging from −78° C. to 200° C. Such coupling reactions between amines and acids are well-known in the art. Alternatively, compounds A where X is bromo or chloro may be reacted with amines B in the presence of a suitable base, such as triethylamine, K₂CO₃, or Cs₂CO₃, to form compounds of Formula I.

Certain compounds of Formula I, wherein the R group is connected to the carbonyl carbon via a nitrogen atom within the R group (forming a urea) may be prepared according to General Scheme B. Amines 13 are activated using methods known to one of skill in the art, wherein LG is a suitable leaving group such as an alkoxy or halo group, and the activated compounds C are then reacted, either in situ or in a separate reaction step, with a suitably substituted amine R²⁰R²¹NH in the presence of a base such as a trialkylamine, to form compounds of Formula I.

Amines B may be prepared according to General Scheme C. The spirocyclic nitrogen in amines D, where PG₁ and PG₂ are suitable nitrogen protecting groups, such as a Boc or CBz group, or PG₁ is R—C(O)— (in which case compounds D may be formed as shown in Scheme A), is deprotected using standard protecting group chemistry to form amines E. Acylation or sulfonylation with suitably substituted acid chlorides or sulfonyl chlorides, in the of a base such as a tertiary amine base, or with suitably substituted acids R^(a)CO₂H under peptide coupling conditions as described in Scheme A, generate compounds F. Where PG₁ is a protecting group, removal of that group generates amines B.

Those having skill in the art will recognize that the starting materials, reagents, and conditions described in the above general schemes may be varied and additional steps employed to produce compounds encompassed by the present inventions. Additionally, one of skill in the art will recognize that the reaction steps presented in the above Schemes may be performed in a different order.

Methods of Chemical Analysis of Example Compounds

Unless otherwise indicated, ¹H NMR spectra were recorded at ambient temperature using one of the following machines: Varian Unity Inova (400 MHz) spectrometer with a triple resonance 5 mm probe, Bruker Avance DRX400 (400 MHz) spectrometer with a triple resonance 5 mm probe, a Bruker Avarice DPX 300 (300 MHz) equipped with a standard 5 mm dual frequency probe for detection of ¹H and ¹³C, a Bruker AVIII (400 MHz) using a BBI Broad Band Inverse 5 mm probe, or a Bruker AVIII (500 MHz) using a QNP (Quad Nucleus detect) 5 mm probe. Chemical shifts are expressed in ppm relative to an internal standard; tetramethylsilane (ppm 0.00). The following abbreviations have been used: br=broad signal, s=singlet, d=doublet, dd=double doublet, t=triplet, q=quartet, m=multiplet.

High Performance Liquid Chromatography—Mass Spectrometry (LC/MS) and supercritical fluid chromatography (SFC) experiments to determine retention times (RT) and associated mass ions, e.g., [M+H]⁻, [M+Na]⁻, [M−H]⁻, were performed using one of the following methods:

Method A Instrument: SHIMADZU LCMS-2010EV

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.1 min, 100% to 5% B in 0.2 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.7 kv.

Method B Instrument: SHIMADZU LCMS-2010EV

LC Parameters: Column: Waters XBridge C18, 3.0×50 mm, 3.5μ; Mobile Phase A: Water/5 mM Ammonium Acetate; Mobile Phase B: Methanol; Gradient: 10% to 100% B in 1.8 min, 100% B for 1.3 min, 100% to 10% B in 0.1 min, then stop; Flow Rate: 0.9 mL/min; Column Temperature: 40° C.; Detector: PDA and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive & Negative); Interface Voltage: 4.0 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.5 kv.

Method C Instrument: SHIMADZU LCMS-2010EV

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile/0.05% TFA; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.1 min, 100% to 5% B in 0.2 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.5 kv.

Method D Instrument: SHIMADZU LC/MS-2010EV

LC Parameters: Column: Waters Xselect C18, 3.0×50 mm, 3.5 μm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: Acetonitrile/0.05% formic acid; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.2 min, 100% to 5% B in 0.1 min, then stop; Flow Rate: 0.9 mL/min; Column Temperature: 35° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive & Negative); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.5 kv.

Method E Instrument: SHIMADZU LCMS-2010EV

LC Parameters: Column: Shim-pack XR-ODS, 3.0×50 mm, 2.2 μm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.0 min, 100% B for 1 min, 100% to 5% B in 0.3 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/ml, in Methanol; Injection Volume: 1 μl. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.3 kv.

Method F Instrument: SHIMADZU LCMS-2010EV

LC Parameters: Column: Shim-pack XR-ODS, 3.0×50 mm, 2.2 μm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.2 min, 100% to 5% B in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 70-900 (m/z); Detector voltage: 1.1 kv.

Method G Instrument: SHIMADZU LC/MS-2020EV

LC Parameters: Column: Shim-pack XR-ODS, 50 mm*3.0 mm, 2.2 um; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.1 min, 100% B for 0.8 min, 100% to 5% B in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Acetonitrile; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.05 kv.

Method H Instrument: SHIMADZU LCMS-2020

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile/0.05% TFA; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.2 min, 100% to 5% B in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.1 kv.

Method I Instrument: SHIMADZU LCMS-2020

LC Parameters: Column: Shim-pack XR-ODS 50*3.0 nm, 2.2 um; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile/0.05% TFA; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.2 min, 100% B to 5% in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 70-900 (m/z); Detector voltage: 1.05 kv.

Method J Instrument: SHIMADZU LCMS-2020 LC Parameters: Column: Shim-pack XR-ODS, 3.0×50 mm, 2.2μ; Mobile Phase A:

Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.2 min, 100% to 5% B in 0.2 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Acetonitrile; Injection Volume: 1 μL.

MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 200° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.05 kv.

Method K Instrument: SHIMADZU LCMS-2020

LC Parameters: Column: Gemini-NX 3u C18 110A; Mobile Phase A: Water/0.04% Ammonia; Mobile Phase B: Acetonitrile; Gradient: 5% to 100% B in 2.0 min, 100% B for 1.1 min, 100% to 5% B in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 35° C.; Detector: 254 nm and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive & Negative); Interface Voltage: 4.5 kv; Heat Block: 200° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 0.75 kv.

Method L Instrument Waters mass-directed Mobile phase A 0.1% H₂O w/NH₄OH Mobile phase B acetonitrile Column Phenomenex Gemini N-X C18, 10 um, 21.5 × 100 mm Column temperature 25° C. LC gradient 5 to 85% in 10 min. LC Flowrate 35 mL/min UV wavelength 254 nm Mass Spectrometer Waters 3100 Ionization ES+

Method M HPLC Waters mass-directed Mobile phase A 0.1% H₂O w/NH₄OH Mobile phase B acetonitrile Column Phenomenex Gemini N-X C18, 10 um, 30 × 100 mm Column temperature 25° C. LC gradient 5 to 50% in 15 min. LC Flowrate 60 mL/min UV wavelength 254 nm Mass Spectrometer Waters 3100 Ionization ES+

Method N Instrument: SHIMADZU LC/MS-2020

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.2 min, 100% B to 5% in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: UV and ELSD; Sample Preparation: 1 mg/mL in Methanol; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 70-900 (m/z); Detector voltage: 1.1 kv.

Method O

Instrument: SHIMADZU UHPLCMS-2020EV (LC-30AD pump, Binary solvent manager, SIL-AC Auto Samples, SPDM20A Detector, Alltech 3300 ELSD Detector LC Parameters: Column: Shim-pack XR-ODS, 1.6 um, 2.0*50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: Acetonitrile/0.1% formic acid; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.1 min, 100% B to 5% in 0.1 min, then stop; Flow Rate: 0.7 mL/min; Column Temperature: 40° C.; Detector: Diode Array Detector (DAD) and ELSD; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.0 kv; Heat Block: 200° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 0.9 kv.

Method P Instrument: SHIMADZU LC/MS-2020

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase 13: Acetonitrile/0.05% formic acid; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.1 min, 100% B to 5% in 0.1 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: PDA and ELSD; Sample Preparation: 1 mg/mL in acetonitrile; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: tuning file; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 0.9 kv.

Method Q Instrument: SHIMADZU LC/MS-2020

LC Parameters: Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: Acetonitrile/0.05% formic acid; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.2 min, 100% B to 5% in 0.2 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: UV and ELSD; Sample Preparation: 1 mg/mL in acetonitrile; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: 4.5 kv; Heat Block: 200° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 0.95 kv.

Method R Instrument: SHIMADZU LC/MS-2020

LC Parameters Column: Shim-pack XR-ODS, 2.2 um, 3.0*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile/0.05% TFA; Gradient: 5% B to 100% B for 1.2 min, 100% B for 0.9 min, 100% B to 5% in 0.2 min, then stop; Flow Rate: 1.0 mL/min; Column Temperature: 40° C.; Detector: PDA and ELSD; Sample Preparation: 1 mg/mL in acetonitrile; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: tuning file; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 1.1 kv.

Method S Instrument: SHIMADZU UHPLC/MS-2020

LC Parameters: Column: Shim-pack XR-ODS, 1.6 um, 2.0*50 mm; Mobile Phase A: Water/0.1% formic acid; Mobile Phase B: Acetonitrile/0.05% formic acid; Gradient: 5% B to 100% B for 2.0 min, 100% B for 1.1 min, 100% B to 5% in 0.1 min, then stop; Flow Rate: 0.7 mL/min; Column Temperature: 40° C.; Detector: PDA and ELSD; Sample Preparation: 1 mg/mL in acetonitrile; Injection Volume: 1 μL. MS Parameters: Interface: ESI (Positive); Interface Voltage: tuning file; Heat Block: 250° C.; Nebulizing Gas: 1.50 L/min; Scan Range: 90-900 (m/z); Detector voltage: 0.85 kv.

Method T Instrument: HPLC Agilent 1200

LC Parameters: Column: Agilent SB C18, 2.1*30 mm, 1.8 um; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 3% B for 0.3 min, 3% B to 95% B in 6.5 min, 95% B for 1.5 min, 95% to 3% B in 0.1 min, then stop; Flow Rate: 0.4 mL/min; Column Temperature: 25° C.; Detector: 254 nm.

MS Parameters: Agilent 6140 Quadrupole LC/MS; Interface: ESI (Positive); Scan Range: 90-1300 amu. Method U Instrument: Waters Acquity UPLC

LC Parameters: Column: Acquity UPLC BEH C18, 1.7 mm, 2.1*50 mm; Mobile Phase A: Water/0.05% TFA; Mobile Phase B: Acetonitrile; Gradient: 2% to 98% B in 17.5 min, 98% B for 1.5 min, equilibrate for 1.5 min, then stop; Flow Rate: 0.6 mL/min; Column Temperature: 40° C.; Detector: 254 nm and 220 nm. MS Parameters: Waters LCT Premier XE; Interface: ESI (Positive); Scan Range: 80-1300 amu; Detector: Time of flight.

The following examples illustrate the preparation of representative compounds of the invention. Unless otherwise specified, all reagents and solvents were of standard commercial grade and were used without further purification.

1. Preparation of Intermediates Intermediate 1: Furo[2,3-c]pyridine-2-carboxylic acid

Step 1. Ethyl 3-hydroxyisonicotinate

A solution of 3-hydroxyisonicotinic acid (495 g, 3.56 mol) in ethanol (7 L) and concentrated H₂SO₄ (250 mL) was heated under reflux for 72 h and then cooled to rt and concentrated under reduced pressure to remove the solvent. The residue was dissolved in water (3 L) and the pH was adjusted to 4 by addition of saturated aqueous NaHCO₃ solution. The resulting precipitate was removed by filtration and the filtrate was extracted with DCM (2 L×3). The combined organic phase was washed with brine, dried over anhydrous Na₇SO₄, and then concentrated under reduced pressure to give ethyl 3-hydroxyisonicotinate (414 g, 70%) as yellow oil.

Step 2. Ethyl 3-(2-ethoxy-2-oxoethoxy)isonicotinate

To a solution of triphenylphosphine (780 g, 2.97 mol) in THF (6 L) at −10° C. was added dropwise diisopropyl azodicarboxylate (600 mL, 2.97 mol). The reaction mixture was stirred at −10° C. for 30 min and then ethyl 3-hydroxyisonicotinate (414 g, 2.48 mol) in THF (1 L) solution was added dropwise. The resulting mixture was stirred at rt for 16 h and then concentrated under reduced pressure. The residue was partitioned between ethyl acetate (4 L) and 1 N HCl (2 L). The aqueous layer was separated and the organic phase was extracted by 1 N HCl (1 L×2). The combined aqueous layers were slowly adjusted to pH 8 by addition of solid NaHCO₃ and then extracted with ethyl acetate (2 L×2). The combined organic layers were dried over anhydrous Na₂SO₄ and then concentrated under reduced pressure to give the title compound (380 g, 61%) as a brown oil.

Step 3. Ethyl 3-hydroxyfuro[2,3-c]pyridine-2-carboxylate

To a suspension of NaH (72 g, 1.8 mol, 60% suspension in mineral oil) in anhydrous THF (2 L) at 0° C. was added dropwise a solution of ethyl 3-(2-ethoxy-2-oxoethoxy)isonicotinate (380 g, 1.5 mol) in THF (1 L) under argon. The reaction mixture was stirred at rt for 16 h and then carefully quenched with ice water (1 L). The resulting mixture was concentrated to a volume of 1.2 L and then diluted with saturated aqueous NaHCO₃ solution (2.5 L), and stirred for an additional 30 min. The precipitated solid was collected by filtration and washed with ethyl acetate (1 L). The filtrate was washed with ethyl acetate (1 L×2) and the aqueous layer was combined with the solid and carefully acidified to a pH of 5 with acetic acid. The resulting solid was collected by filtration and dried under vacuum to give the title compound (210 g, 68%) as a yellow solid.

Step 4. Ethyl 3-(((trifluoromethyl)sulfonyl)oxy)furo[2,3-c]pyridine-2-carboxylate

To a solution of ethyl 3-hydroxyfuro[2,3-c]pyridine-2-carboxylate (210 g, 1.01 mol) and pyridine (107 mL, 1.3 mol) in anhydrous DCM (3 L) at 0° C. was added dropwise triflic anhydride (203 g, 1.2 mol). The reaction mixture was stirred at rt for 16 h and then quenched with ice water (1 L). The aqueous layer was extracted with DCM (1 L×2) and the combined organic layer was dried over anhydrous Na₂SO₄ and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with 10% ethyl acetate/petroleum ether to give the title compound (298 g, 87%) as a white solid.

Step 5. Ethyl furo[2,3-c]pyridine-2-carboxylate

To a solution of ethyl 3-(((trifluoromethyl)sulfonyl)oxy)furo[2,3-c]pyridine-2-carboxylate (298 g, 0.88 mol) in ethanol (3 L) was added 10% Pd/C (30 g) and triethylamine (281 mL, 2.02 mol). The reaction mixture was stirred under an atmosphere of hydrogen for 16 h and then filtered through a pad of diatomaceous earth. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography eluting with 20% ethyl acetate/petroleum ether to give the title compound (158 g, 94%) as a pale yellow solid.

Step 6

To a solution of ethyl furo[2,3-c]pyridine-2-carboxylate (158 g, 0.83 mol) in water:THF:MeOH (1:1:1, 2.4 L) was added KOH (139 g, 2.49 mol). The reaction mixture was stirred at rt for 16 h and then concentrated to a volume of 750 mL. To this residue was added acetic acid until pH˜4. The resulting solids were collected by filtration, washed with water (300 mL×2) and dried in a vacuum oven overnight to give the title compound (101 g, 75%) as a pale yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.07 (s, 1H), 8.47 (d, J=5.6 Hz, 1H), 7.80 (d, J=5.2 Hz, 1H), 7.61 (s, 1H), MS (ESI+) m/z: 164 [M+H]⁺.

Intermediate 2: Imidazo[1,2-a]pyridine-6-carboxylic acid

Step 1. Imidazo[1,2-a]pyridine-6-carboxylic acid hydrochloride salt

A mixture of 2-chloroacetaldehyde (277 g, 40%) and 6-aminonicotinic acid (150 g) in ethanol (330 mL) was heated to reflux and stirred for 8 h. After cooling, a solid precipitated and was isolated by vacuum filtration, then washed with ethanol and dried under vacuum to give the title compound as a light yellow solid (1.78 g, 82%).

Step 2

Imidazo[1,2-a]pyridine-6-carboxylic acid hydrochloride salt (170 g) was diluted with water (600 mL) and heated until a clear solution resulted, then an aqueous solution of NaOH (2 M) was added slowly to adjust the pH=5-6. The reaction mixture was cooled to 0° C. using an ice-H₂O bath. The resulting precipitate was collected by vacuum filtration, then washed with ethanol and dried under vacuum to give the title product (107.2 g, 77%) as a light yellow powder. ¹H NMR (400 MHz, DMSO-d₆) δ 13.76-12.82 (br, 1H), 9.28 (s, 1H), 8.10 (s, 1H), 7.68 (s, 1H), 7.64-7.56 (m, 2H), MS (ESI+) m/z: 163 [M+H]⁻.

Intermediate 3: Imidazo[1,2-a]pyrimidine-6-carboxylic acid

Step 1. Sodium (Z)-2-(dimethoxymethyl)-3-methoxy-3-oxoprop-1-en-1-olate

Methyl 3,3-dimethoxypropanoate (100 g, 675 mmol) and methyl formate (81 g, 1350 mmol) were dissolved in anhydrous THF (450 mL). Sodium hydride (60% dispersion; 32.4 g, 810 mmol, 1.2 eq.) was then added slowly in portions at 0° C. The reaction mixture was stirred at rt for 1 h, then was heated at 50° C. for 3 h. During this period, H₂ evolution was observed. After cooling to rt, the solvent was then removed under reduced pressure to give the crude product which was directly used in the next step without further purification.

Step 2. Methyl 2-aminopyrimidine-5-carboxylate

The crude enolate from step 1 was dissolved in DMF (200 mL), and guanidine hydrochloride (64 g, 670 mmol) was added. The mixture was heated at 100° C. under N₂ for 3 h. After cooling to rt, water was added and the mixture was cooled with an ice-water bath. The resulting precipitate was collected by vacuum filtration and dried under vacuum to give the desired product (63 g, 61% yield for 2 steps).

Step 3. Methyl imidazo[1,2-a]pyrimidine-6-carboxylate

To a mixture of 2-bromo-1,1-diethoxyethane (100.6 g, 0.51 mol) and methyl 2-aminopyrimidine-5-carboxylate (63 g, 0.41 mol) in ethanol (300 mL) was added concentrated HBr (40%) (55 g). The reaction mixture was heated to reflux for 3 h under N₂. After cooling to rt, the mixture was further cooled with an ice-water bath. The resulting precipitate was collected by vacuum filtration and dried under vacuum overnight to give the desired product (92 g, 87%).

Step 4

Into a round bottom flask containing methyl imidazo[1,2-a]pyrimidine-6-carboxylate (92 g, 356.5 mmol), was added water (200 mL). NaOH (6 N in H₂O, 2.5 eq.) was then added dropwise with stirring at rt. After stirring at rt for 1 h, the mixture was cooled with an ice-water bath and concentrated HCl was added (pH=5-6). The resulting mixture was concentrated under reduced pressure to approximately 150 ml. (3/4 volume) and cooled with an ice-water bath. The resulting precipitate was collected by vacuum filtration, washed with cold water (50 mL) and dried to give the title compound as an off-white solid (46 g, 79%). ¹H NMR (DMSO-d₆, 400 MHz) δ 9.29 (d, J=2.0 Hz, 1H), 8.89 (d, J=2.0 Hz, 1H), 7.94 (s, 1H), 7.70 (s, 1H), MS (m/z, ES⁻): 164.1 [M+H]⁺, 186.1 [M+Na]⁺.

Intermediate 4: 1H-Pyrazolo[3,4-b]pyridine-5-carboxylic acid

Step 1. 1-(4-Methoxybenzyl)-1H-pyrazol-5-amine

To a solution of acrylonitrile (30 mL, 455 mmol) in THF (250 mL), NH₂NH₂.H₂O (23.19 mL, 478 mmol) was added drop-wise at 0° C. After addition was complete, the mixture was stirred at rt for 2 h, then 4-methoxybenzaldehyde (55.4 mL, 455 mmol) was added drop-wise. The mixture was stirred at rt overnight, then at reflux for 2 h. After cooling to rt the mixture was quenched by addition of 300 mL of ice water. The mixture was extracted with ethyl acetate (3×), then the combined organic layers were extracted with 1 N HCl. The aqueous layer was neutralized with aqueous 10 N NaOH solution, then extracted with ethyl acetate. The organic layer was washed with H₂O and brine, then dried over Na₂SO₄. Filtration, concentration, and recrystrallization with Et₂O gave the target compound as a white solid (50 g, 60%).

Step 2. Ethyl 4-hydroxy-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

1-(4-Methoxybenzyl)-1H-pyrazol-5-amine (3.94 g, 19.39 mmol), followed by diethyl 2-(ethoxymethylene)malonate (4 mL, 20 mmol) was added to a 200 mL round bottom flask fitted with a distillation head to remove ethanol. The mixture was heated to 130° C. for 45 min, then 10 mL of diphenyl ether was added and the temperature was raised to 240° C. for 2 h. The reaction mixture was then cooled to rt and diethyl ether (100 mL) was added. The resulting precipitate was collected by vacuum filtration and dried under vacuum to afford the target compound as a white solid (4 g, 62%).

Step 3. Ethyl 4-chloro-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

POCl₃ (10 mL) was added to ethyl 4-hydroxy-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (7.5 g, 19.39 mmol). The mixture was stirred at 60° C. for 3 h. The mixture was poured into ice water and the resulting precipitate was collected by vacuum filtration and dried under vacuum to afford the target compound a light yellow solid (6.4 g, 80%).

Step 4. Ethyl 1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

To a solution of ethyl 4-chloro-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (5.9 g, 17 mmol) in THF (50 mL), triethylamine (1.7 g, 17 mmol), followed by Pd(OH)₂/C (300 mg) was added. The mixture was stirred at rt for 3 h under H₂. The mixture was filtered and concentrated. The residue was dissolved in ethyl acetate and washed with saturated aqueous NaHCO₃ solution and brine, then dried over Na₂SO₄. Filtration and concentration gave target compound as a light gray solid (5.3 g, 100%).

Step 5

Ethyl 1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (4.4 g, 14 mmol) was dissolved in TEA (158 mL) and heated to 80° C. The mixture was stirred at 80° C. for 4 h, then was concentrated to dryness. The residue was poured into ice water, then aqueous NaOH solution (2 M) was added until the pH was approximately 14. The solid formed was removed by filtration, and the aqueous layer was washed with ethyl acetate. To the aqueous layer was added concentrated HCl was added until the pH was approximately 7. The resulting precipitate was collected by vacuum filtration and dried under vacuum to afford the title compound as a white solid (2.1 g, 80%). ¹H NMR (400 MHz. DMSO-d₆) δ 14.38-13.62 (br, 1H), 9.07 (d, J=1.6 Hz, 1H), 8.81 (d, J=1.6 Hz, 1H), 8.32 (s, 1H), MS (m/z, ESI+): 164 [M+H]⁺.

Intermediate 5: 1H-Pyrrolo[3,2-c]pyridine-2-carboxylic acid

Step 1. 3-Iodopyridin-4-amine

To a 2 L 3-necked flask was added a solution of 38 mL of concentrated sulfuric acid in 200 mL water. The solution was cooled with an ice-water bath, then 4-aminopyridine (200 g, 2.12 mol) and acetic acid (700 mL) were added in batches. The mixture was then heated to reflux. Iodine (189 g, 0.745 mol) and periodic acid dihydrate (97 g, 0.424 mol) were both equally divided into four parts. One batch of iodine was added and then one batch of periodic acid dihydrate was added 15 min later. After 30 min, a new batch of iodine and periodic acid dihydrate were added in the same way. When all four batches of iodine and periodic acid dehydrate were added, the mixture was kept refluxing for an additional 3 h. After cooling to rt the reaction mixture was slowly poured into water while stirring, then a 40% solution of NaOH in water was added until pH>9. Na₂SO₃ was added to destroy the unreacted iodine. After cooling to rt, a filtration was performed. The collected solid was further purified by recrystallization in chloroform to give the desired product (184 g, 39%).

Step 2

To a 2 L 3-necked flask was added DMF (700 mL), triethylene diamine (168 g, 1.5 mol), and 4-amino-3-iodopyridine (24, 110 g, 0.5 mol). The mixture was cooled with an ice-water bath and pyruvic acid (132 g, 1.5 mol) was slowly added, followed by palladium acetate (4.49 g, 0.02 mol). Under nitrogen atmosphere, the mixture was heated to 115° C. The reaction generated effervescence. The reaction mixture was kept at 115-120° C. for 11 h. The mixture was concentrated under reduced pressure. The residue was poured into water (500 mL), and concentrated HCl was added to adjust pH to <1. The mixture was cooled by adding ice and a filtration was performed. The cake thus obtained was a brownish black solid.

The above cake was added into 500 mL of water. Concentrated HCl was added (to ensure complete protonation) followed by 5 g of active carbon. The mixture was heated to reflux for 20 min and then filtration was performed while hot. The solid was discarded and the hot filtrate was placed in a refrigerator to allow the HCl salt of the desired product to precipitate. Upon cooling, filtration was performed which afforded a dark brown solid with a wet weight of 48 g as the HCl salt of the desired product.

The solid was then added to 250 mL of water and the mixture was heated until a clear solution resulted. Solid NaOH was slowly added to adjust pH to 5-6, then active carbon and an additional 500 mL of water was added. The mixture was heated to reflux for 30 min, then filtration was performed while hot. The resulting cake was added to 750 mL of water, heated to reflux, and filtered again. The cake thus obtained was discarded. The two batches of filtrate were combined and cooled in a refrigerator. The resulting precipitate was collected by vacuum filtration, then washed with ethanol to give the title compound as a slightly yellow solid (25 g, 31%). MS (m/z, ES⁻): 161.1 [M-1], 323.1 [2M-1]. ¹H NMR (DMSO-d₆, 400 MHz) δ 12.20 (br s, 1H), 8.97 (s, 1H), 8.27 (d, J=5.6 Hz, 1H), 7.41 (d, J=6.0 Hz, 1H), 7.23 (s, 1H).

Intermediate 6: Thieno[2,3-c]pyridine-2-carboxylic acid

Step 1. 3,5-Dibromoisonicotinaldehyde

Lithium diisopropylamide (507 mmol, 1.2 eq.) was added to 200 mL of dry THF at −78° C. under N₂. A solution of 3,5-dibromopyridine (100 g, 424 mmol) in 537 mL of dry THF was then added drop-wise over 30 min. The reaction mixture was stirred at −78° C. for 1 h. Ethyl formate (34.4 g, 465 mmol) was added drop-wise and stirred at −78° C. for 30 min, then the reaction mixture was poured into ice-cold saturated aqueous NaHCO₃ solution. The mixture was extracted with 3×500 mL of ethyl acetate. The organic layer was concentrated to provide a brown solid, which was filtered through a pad of silica gel (eluted with dichloromethane) to give the title compound as a yellow powder (70 g, 63%).

Step 2: Methyl 4-bromothieno[2,3-c]pyridine-2-carboxylate

3,5-Dibromoisonicotinaldehyde (80 g, 303 mmol), followed by cesium carbonate (98 g, 302 mmol) was added to a 2 L round bottom flask containing THF (1.3 L) under N₂. Methyl mercaptoacetate (32 g, 302 mmol) was added and the mixture was heated at 60° C. overnight. After cooling to rt, ethyl acetate was added and the organic layer was washed with water, aqueous saturated NaHCO₃ solution, and brine, then dried over Na₂SO₄ and filtered to give a white solid. The crude product was purified by recrystallization from ethyl acetate to give the desired product (60 g, 73%).

Step 3. Methyl thieno[2,3-c]pyridine-2-carboxylate

Methyl 4-bromothieno[2,3-c]pyridine-2-carboxylate (115 g, 423 mmol), triethylamine (42.7 g, 423 mmol), THF (1.5 L), and MeOH (500 mL) were mixed and degassed. Under nitrogen, palladium on carbon (10%, 14.7 g, 13.9 mmol) was added. The mixture was hydrogenated with a Parr apparatus at 45 psi H₂ for 3 days. The catalyst was filtered off and the filtrate was concentrated to give the desired compound as a white solid (65 g, 80%).

Step 4

A three necked 2 L round bottom flask equipped with an overhead stirrer and thermocouple was charged with methyl thieno[2,3-c]pyridine-2-carboxylate (130 g, 674 mmol) and water (650 mL). Aqueous sodium hydroxide solution (10 N) was added with stirring at 20° C. Over the next 20 min, the temperature rose to 25° C. and the solid dissolved. After 1 h, concentrated HCl (1.5 eq.) was slowly added to the reaction mixture with rapid stirring, generating a thick slurry. After stirring for 1 h, the slurry was filtered and the solid was dried under vacuum to give the title compound as a white solid (105.5 g, 88%). MS (m/z, ES⁻): 178.0 [M-1]. ¹H-NMR (DMSO-d₆, 400 MHz) δ 12.24 (br s, 1H), 8.97 (s, 1H), 8.27 (d, J=6.0 Hz, 1H), 7.40 (d, J=5.6 Hz, 1H), 7.23 (s, 1H).

Intermediate 7: Imidazo[1,2-b]pyridazine-6-carboxylic acid

Step 1. 6-Chloro-imidazo[1,2-b]pyridazine

A solution of 6-chloro-1,2-diazinan-3-amine (10 g, 73.75 mmol, 1.00 equiv), 2-bromo-1,1-dimethoxyethane (50 g, 295.83 mmol, 4.01 equiv), and HBr (40%, 45 mL) in ethanol (100 mL) was stirred overnight at 90° C. The majority of the ethanol was removed under reduced pressure then the pH value of the solution was adjusted to 10 with 5% aqueous potassium carbonate solution. The resulting mixture was extracted with 6×500 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1/2˜1/1) to give 6.5 g (57%) of the title compound as a yellow solid. ¹H NMR (300 MHz, CDCl₃) δ 7.95 (s, 1H), 7.91 (s, 1H), 7.80 (s, 1H), 7.05 (d, J=9.3 Hz, 1H).

Step 2. Imidazo[1,2-b]pyridazine-6-carboxylic acid methyl ester

A mixture of 6-chloro-imidazo[1,2-b]pyridazine (200 mg, 1.30 mmol, 1.00 equiv), bis(triphenylphosphine)palladium(II) dichloride (200 mg, 0.28 mmol, 0.22 equiv), and triethylamine (0.5 mL) in methanol (4 mL) was stirred under carbon monoxide (10 atm) in a 50-mL pressure reactor overnight at 110° C. The solid material was removed by filtration. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1/1) to give 100 mg (43%) of the title compound as a yellow solid. ¹H NMR (300 MHz, CDCl₃) δ 8.16 (s, 1H), 8.08 (d, J=9.6 Hz, 1H), 7.94 (s, 1H), 7.77 (d, J=9.6 Hz, 1H), 4.09 (s, 3H).

Step 3

A mixture of imidazo[1,2-b]pyridazine-6-carboxylic acid methyl ester (900 mg, 5.08 mmol, 1.00 equiv) and 5% aqueous sodium hydroxide solution (15 mL, 3.75 equiv) in THF (3 mL) was stirred overnight at rt. The pH value of the solution was adjusted to 2 with 1 M HCl. The resulting mixture was concentrated under vacuum to give 3 g of crude title product as a yellow solid. The crude product was used without further purification. LC/MS (Method A, ESI): RT=0.43 min, m/z=164.0 [M+H]⁺.

Intermediate 8: Pyrazolo[1,5-a]pyridine-5-carboxylic acid

Step 1. 1-Amino-4-methoxypyridinium iodide

A solution of aminooxysulfonic acid (11.4 g, 100.80 mmol, 0.50 equiv) and 4-methoxypyridine (22 g, 201.60 mmol, 1.00 equiv) in water (200 mL) was stirred under nitrogen for 0.5 h at 90° C. Potassium carbonate (14 g, 101.30 mmol, 0.50 equiv) was added at rt. The resulting mixture was concentrated under vacuum then ethanol (150 mL) was added to dissolve the residue. The insoluble material was removed by filtration. The filtrate was cooled to −20° C. and then hydroiodic acid (16 g, 40%) was added. The resulting solution was stirred for 1 h at −20 T. The precipitated product was collected by filtration and washed with cold ethanol to give 9.3 g (46%) of the title compound as a white solid. TLC: 1:5 MeOH/DCM, R_(f)=0.02.

Step 2. 5-Methoxy-pyrazolo[1,5-a]pyridine-3-carboxylic acid methyl ester

A mixture of 1-amino-4-methoxypyridinium iodide (6 g, 23.80 mmol, 1.00 equiv), potassium carbonate (5 g, 36.18 mmol, 1.50 equiv), and methyl propiolate (2 g, 23.79 mmol, 1.00 equiv) in DMF (50 mL) was stirred under nitrogen for 4 h at rt. After the reaction completed, the mixture was concentrated under vacuum. The residue was dissolved in 150 mL of dichloromethane and then washed with 1×20 mL of saturated aqueous sodium bicarbonate solution. The organic layer was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/hexane (1:3) to give 1.5 g (31%) of title product as a solid. LC/MS (Method D, ESI): RT=1.30 min, m/z=207.0 [M+H]⁺.

Step 3. Pyrazolo[1,5-a]pyridin-5-ol

A mixture of methyl 5-methoxypyrazolo[1,5-a]pyridine-3-carboxylate (100 mg, 0.48 mmol, 1.00 equiv) in 40% HBr (5 mL) was stirred for 16 h at 100° C. The reaction mixture was cooled to rt and the pH value of the solution was adjusted to 8 with 5 M potassium hydroxide solution. The resulting solution was extracted with 2×50 mL of ether. The organic layers were combined and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:3 to 1:1) to yield 20 mg (31%) of the title compound as a white solid. LC/MS (Method D, ESI): RT=0.41 min, m/z=135.0 [M−H].

Step 4. Trifluoro-methanesulfonic acid pyrazolo[1,5-a]pyridin-5-yl ester

A mixture of pyrazolo[1,5-a]pyridin-5-ol (300 mg, 2.24 mmol, 1.00 equiv) and trifluoromethanesulfonic anhydride (0.5 mL) in pyridine (5 mL) was stirred for 10 h at rt. The resulting mixture was concentrated under vacuum and the residue was dissolved in 100 mL of dichloromethane. The mixture was washed with 1×10 mL of sodium bicarbonate solution. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:3) to yield 200 mg (34%) of the title compound as a solid, LC/MS (Method B, ESI): RT=2.13 min, m/z=267.0 [M+H]⁺.

Step 5. Pyrazolo[1,5-a]pyridine-5-carboxylic acid methyl ester

A mixture of trifluoro-methanesulfonic acid pyrazolo[1,5-a]pyridin-5-yl ester (200 mg, 0.75 mmol, 1.00 equiv), triethylamine (227 mg, 2.24 mmol, 3.00 equiv), DMSO (98 mg, 1.25 mmol, 1.67 equiv), and bis(triphenylphosphine)palladium(II) dichloride (53 mg, 0.08 mmol, 0.10 equiv) in methanol (20 mL) was stirred under carbon monoxide (10 atm) for 16 h at 100° C. in a 50-mL pressure reactor. After the reaction completed, the reaction mixture was cooled to rt and the mixture was concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:3) to afford 130 mg of the title compound as a solid. LC/MS (Method H, ESI): RT=1.36 min, m/z=177.0 [M+H]⁺.

Step 6

A mixture of pyrazolo[1,5-a]pyridine-5-carboxylic acid methyl ester (130 mg, 0.74 mmol, 1.00 equiv) and potassium hydroxide (1 g, 17.82 mmol, 24.15 equiv) in methanol (2 mL), THF (2 mL), and water (5 mL) was stirred for 12 h at rt. The reaction mixture was washed with 2×50 mL of ethyl acetate. The aqueous layer was collected and the pH value of the solution was adjusted to 6 with 1 N HCl. The solution was extracted with 5×50 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give 100 mg (84%) the title compound as a yellow solid. LC/MS (Method G, ESI): RT-1.32 min, m/z=163.0 [M+H]⁺.

Intermediate 9: 1H-Pyrazolo[4,3-b]pyridine-6-carboxylic acid

Step 1. 5-Bromo-2-methyl-pyridin-3-ylamine

To a stirred mixture of iron filings (5 g, 89.29 mmol, 3.88 equiv) and ammonium chloride (1 g, 18.70 mmol, 0.81 equiv) in ethanol (66 mL) and water (33 mL) was added a solution of 5-bromo-2-methyl-3-nitropyridine (5 g, 23.04 mmol, 1.00 equiv) in ethanol (50 mL) dropwise at 90° C. The reaction mixture was stirred for 10 min at 90° C. and then cooled to rt. The solid material was removed by filtration. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:2) to yield 1.6 g (37%) of the title compound as a yellow solid. LC/MS (Method I, ESI): RT=0.81 min, m/z=187.0; 189.0 [M+H]⁺.

Step 2. N-(5-Bromo-2-methyl-pyridin-3-yl)-acetamide

A solution of 5-bromo-2-methyl-pyridin-3-ylamine (3 g, 16.04 mmol, 1.00 equiv) in acetic anhydride (20 mL) and acetic acid (10 mL) was stirred overnight at rt. The resulting mixture was concentrated under vacuum to give 2.6 g (71%) of the title compound as a light yellow solid. LC/MS (Method I, ESI): RT=1.05 min, m/z=229.0; 231.0 [M+H]⁺.

Step 3. 1-(6-Bromo-pyrazolo[4,3-b]pyridin-1-yl)-ethanone

A mixture of N-(5-bromo-2-methyl-pyridin-3-yl)-acetamide (3.5 g, 15.28 mmol, 1.00 equiv), isopentyl nitrite (4 g, 34.73 mmol, 2.27 equiv), potassium acetate (20 g), and acetic anhydride (30 mL) in toluene (150 mL) was stirred under nitrogen overnight at 90° C. The reaction mixture was cooled to rt and the solid material was removed by filtration. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to give in 2 g (55%) of the title compound as a light yellow solid. LC/MS (Method I, ESI): RT=1.44 min, m/z=240.0; 242.0 [M−H]⁻.

Step 4. 1H-Pyrazolo[4,3-b]pyridine-6-carboxylic acid methyl ester

A mixture of 1-(6-bromo-pyrazolo[4,3-b]pyridin-1-yl)-ethanone (2 g, 8.33 mmol, 1.00 equiv), bis(triphenylphosphine)palladium(II) dichloride (1 g, 1.42 mmol, 0.17 equiv), and triethylamine (2.5 mL) in methanol (70 mL) was stirred overnight under carbon monoxide (10 atmospheres) at 100° C. in a 100 mL pressure reactor. The reaction mixture was cooled to rt and the solid material was removed by filtration. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to afford 0.8 g (54%) of the title compound as a light yellow solid. TLC: 1:1 ethyl acetate/petroleum ether, R_(f)=0.2.

Step 5

A solution 1H-pyrazolo[4,3-b]pyridine-6-carboxylic acid methyl ester (200 mg, 1.13 mmol, 1.00 equiv) and sodium hydroxide (200 mg, 5.00 mmol, 4.43 equiv) in water (10 mL) was stirred overnight at rt. After the reaction was complete, the pH value of the solution was adjusted to 3 with concentrated HCl. The resulting mixture was concentrated under vacuum to give 1 g of crude title product as a light yellow solid. LC/MS (Method I, ESI): RT=0.91 min, m/z=164.0; 242.0 [M+H]⁺.

Intermediate 10: [1,2,4]Triazolo[1,5-a]pyridine-6-carboxylic acid

Step 1. N′-(5-Bromo-pyridin-2-yl)-N,N-dimethyl-formamidine

A solution of 5-bromopyridin-2-amine (4 g, 23.12 mmol, 1.00 equiv) and N,N-dimethylformamide dimethyl acetal (9.6 mL, 3.00 equiv) in DMF (30 mL) was stirred under nitrogen for 12 h at 130° C. The reaction mixture was cooled to rt and then concentrated under vacuum to give 4 g (76%) of the title compound as an oil. TLC: 1:5 MeOH/DCM, R_(f)=0.6.

Step 2. 6-Bromo-[1,2,4]triazolo[1,5-a]pyridine

To a solution of N′-(5-bromo-pyridin-2-yl)-N,N-dimethyl-formamidine (4 g, 17.54 mmol, 1.00 equiv) in methanol (40 mL) maintained under nitrogen at 0° C. was added pyridine (4 mL, 2.00 equiv) and (aminooxy)sulfonic acid (3.6 g, 31.83 mmol, 1.30 equiv). The resulting solution was stirred for 12 h at rt. After the reaction completed, the mixture was concentrated under vacuum. The residue was diluted with 150 mL of ethyl acetate then washed with 1×50 mL of saturated aqueous sodium carbonate solution and 2×50 mL of water. The organic layer was dried over anhydrous sodium sulfate then concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/hexane (1:1) to give 2.5 g (72%) title compound as a solid. LC/MS (Method D, ESI): RT=1.15 min, m/z=198.0 [M+H]⁺.

Step 3. [1,2,4]Triazolo[1,5-a]pyridine-6-carboxylic acid methyl ester

A mixture of 6-bromo-[1,2,4]triazolo[1,5-a]pyridine (2.4 g, 12.12 mmol, 1.00 equiv), bis(triphenylphosphine)palladium(II) dichloride (800 mg, 1.14 mmol, 0.10 equiv) and triethylamine (4 g, 39.53 mmol, 3.00 equiv) in DMSO (1.6 g, 20.48 mmol, 1.67 equiv) and methanol (50 mL) was stirred under carbon monoxide (10 atm) for 20 h at 100° C. The reaction mixture was cooled to rt and quenched with brine (50 mL). The resulting solution was extracted with ethyl acetate (3×40 mL). The combined organic layers were dried over anhydrous sodium sulfate then concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/hexane (1:1) to give 0.98 g (46%) of the title compound as a crude solid. LC/MS (Method C, ESI): RT=1.04 min, m/z=178.0 [M+H]⁺.

Step 4

A solution of [1,2,4]triazolo[1,5-a]pyridine-6-carboxylic acid methyl ester (200 mg, 1.13 mmol, 1.00 equiv) in THF (2 mL) was added to a solution of potassium hydroxide (1 g, 17.82 mmol, 15.79 equiv) in water (10 mL). The resulting mixture was stirred for 10 h at rt. After the reaction completed, the pH value of the solution was adjusted to 5-6 with 1 N HCl. The mixture was extracted with 3×50 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give 112 mg (61%) of the title compound as a solid. LC/MS (Method C, ESI): RT=0.9 min, m/z=164.0 [M+H]⁺.

Intermediate 11: Pyrazolo[1,5-a]pyrimidine-5-carboxylic acid

Step 1. 4H-Pyrazolo[1,5-a]pyrimidin-5-one

A solution of 1H-pyrazol-3-ylamine (7 g, 84.24 mmol, 1.00 equiv) and ethyl prop-2-ynoate (50 mL) in dioxane (10 g, 1.21 equiv) was stirred under nitrogen overnight at 110° C. The reaction mixture was cooled to rt and the precipitated product was collected by filtration to give 4 g (36%) of the title compound as a light brown solid. ¹H NMR (300 MHz, DMSO-d₆) δ 12.04 (s, 1H), 8.41-8.44 (m, 1H), 7.71 (d, J=1.8 Hz, 1H), 5.88 (d, J=8.1 Hz, 1H), 5.77 (m, 1H).

Step 2. 5-Chloro-pyrazolo[1,5-a]pyrimidine

A solution of 4H-pyrazolo[1,5-a]pyrimidin-5-one (1 g, 7.40 mmol, 1.00 equiv) in phosphorus oxychloride (15 mL) was stirred under nitrogen for 2 h at 120° C. The reaction mixture was cooled to rt then concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:2) to give 0.6 g (53%) of the title compound as a light yellow solid. LC/MS (Method I, ESI): RT=1.21 min, m/z=154.0 [M+H]⁺.

Step 3. Pyrazolo[1,5-a]pyrimidine-5-carboxylic acid methyl ester

A mixture of 5-chloro-pyrazolo[1,5-a]pyrimidine (2 g, 13.02 mmol, 1.00 equiv), triethylamine (4 mL), methanol (80 mL), and bis(triphenylphosphine)palladium(II) dichloride (1 g, 1.42 mmol, 0.11 equiv) was stirred in a 100-mL pressure reactor overnight at 100° C. under 10 atmospheres of carbon monoxide. The reaction mixture was cooled to rt then concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to yield 1.2 g (52%) of the title compound as a light yellow solid. LC/MS (Method I, ESI): RT=1.09 min, m/z=178.0 [M+H]⁺.

Step 4

To a solution of methyl pyrazolo[1,5-a]pyrimidine-5-carboxylic acid methyl ester (100 mg, 0.56 mmol, 1.00 equiv) in acetic acid (5 mL) was added concentrated HCl (37%, 5 mL). The resulting solution was stirred for 3 h at 120° C., then concentrated under vacuum. The residue was dissolved in 3 mL of water and then adjusted to pH 5 with saturated aqueous sodium carbonate solution. The precipitated product was collected by filtration then air-dried to give 0.08 g (87%) of pyrazolo[1,5-a]pyrimidine-5-carboxylic acid as a light yellow solid. LC/MS (Method 1, ESI): RT=0.95 min, m/z=164.0 [M+H]⁺.

Intermediate 12: 3-tert-Butylamino-imidazo[1,2-a]pyridine-6-carboxylic acid

Step 1. 3-tert-Butylamino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of methyl 6-aminopyridine-3-carboxylate (3.8 g, 24.98 mmol, 1.00 equiv) and 2-oxoacetic acid hydrate (3.9 g, 42.39 mmol, 1.70 equiv) in methanol (120 mL) was added perchloric acid (250 mg, 2.50 mmol, 0.10 equiv). The reaction mixture was stirred for 30 min and 2-isocyano-2-methylpropane (2.08 g, 25.02 mmol, 1.00 equiv) was then added. The reaction mixture was stirred for 12 h at rt and then concentrated under vacuum. The residue was purified on a silica gel column eluted with dichloromethane/ethyl acetate (2:1) to give 850 mg (14%) of the title compound as a yellow solid. ¹H NMR (300 MHz, CDCl₃) δ 8.97-8.96 (dd, J=0.9, 1.5 Hz, 1H), 7.69-7.65=4.2, 9.6 Hz, 1H), 7.53-7.50 (dd, J=4.2, 9.6 Hz, 1H), 7.39 (s, 1H), 3.96 (s, 3H), 1.23 (s, 9H).

Step 2. Sodium 3-tert-Butylamino-imidazo[1,2-a]pyridine-6-carboxylate

To a solution of 3-tert-butylamino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester (300 mg, 1.21 mmol, 1.00 equiv) in methanol (5 mL) was added a solution of sodium hydroxide (97 mg, 2.42 mmol, 2.00 equiv) in water (5 mL). The resulting solution was stirred for 1.5 h at 46° C. The reaction mixture was cooled to rt and then quenched by the addition of 0.15 mL of HCl. The resulting mixture was concentrated under vacuum to give 345.6 mg (crude) of the title product as a yellow solid. LC/MS (Method I, ESI): RT=1.02 min, m/z=234.0 [M+H−22]⁻.

Step 3. Sodium 3-tert-butylamino-imidazo[1,2-a]pyridine-6-carboxylate (300 mg, 1.17 mmol, 1.00 equiv) was dissolved in acetic acid (10 mL) and then concentrated under vacuum. The residue was purified on a silica gel column eluted with dichloromethane/methanol (20:1) to give 150 mg (54%) of the title compound as a yellow solid. LC/MS (Method N, ESI): RT=0.94 min, m/z=234.0 [M+H]⁺.

Intermediate 13: 2,3-Dihydro-1H-pyrrolo[3,4-c]pyridine

Step 1. Ethyl N-(prop-2-yn-1-yl)carbamate

To a solution of prop-2-yn-1-amine (11.5 g, 208.79 mmol, 1.00 equiv) and sodium hydroxide (9.1 g, 227.50 mmol, 1.09 equiv) in water (40 mL) and toluene (110 mL) maintained under nitrogen was added ethyl chloroformate (23.9 g, 220.23 mmol, 1.05 equiv) dropwise in 20 min with stirring at 10° C. The resulting solution was stirred overnight at rt then extracted with 3×100 mL of toluene. The combined organic layers were dried over anhydrous sodium sulfate then concentrated under vacuum to give 15 g (57%) of ethyl N-(prop-2-yn-1-yl)carbamate as a light yellow oil. TLC: ethyl acetate/petroleum ether (1:2), R_(f)=0.5.

Step 2. Pyrimidine-5-carboxaldehyde

To a solution of 5-bromopyrimidine (2 g, 12.58 mmol, 1.00 equiv) in THF (20 mL) placed in a 50-mL 3-necked round-bottom flask purged and maintained with an inert atmosphere of nitrogen was added n-butyllithium (1.1 mL) at −78° C. The reaction mixture was stirred at −78° C. for another 2 h. Ethyl formate (5.2 mL) was then added and the resulting solution was stirred for 2 h at −78° C. The resulting mixture was warmed to 0° C. and washed with 50 mL of brine. The organic layer was dried with anhydrous sodium carbonate and concentrated. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:1) to give 11 g of crude pyrimidine-5-carboxaldehyde as a yellow oil. TLC: ethyl acetate/petroleum ether (1/I), R_(t)=0.2.

Step 3. Pyrimidin-5-ylmethanol

A mixture of pyrimidine-5-carboxaldehyde (2 g, 18.50 mmol, 1.00 equiv) and sodium borohydride (2 g) in methanol (100 mL) was stirred at 0-10° C. for 30 min. The reaction mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with dichloromethane/methanol (50:1) to yield 1.2 g (59%) of pyrimidin-5-ylmethanol as a light yellow solid. LC/MS (Method N, ESI): RT=0.74 min, m/z=111.0 [M+H]⁻.

Step 4. 5-(Chloromethyl)pyrimidine

To a solution of pyrimidin-5-ylmethanol (1.1 g, 10 mmol, 1.00 equiv) in dichloromethane (30 mL) was added thionyl chloride (2 mL) dropwise with stirring. The resulting solution was stirred at rt for 2 h then concentrated in vacuum to give 1.1 g of crude 5-(chloromethyl)pyrimidine as a yellow oil. TLC: ethyl acetate/petroleum ether (1:1), R_(f)=0.4.

Step 5. Ethyl N-(prop-2-yn-1-yl)-N-(pyrimidin-5-ylmethyl)carbamate

A mixture of ethyl N-(prop-2-yn-1-yl)carbamate (1.27 g, 9.99 mmol, 1.00 equiv) benzyltriethylammonium chloride (500 mg, 2.60 mmol, 0.26 equiv), 5-(chloromethyl)pyrimidine (1.28 g, 9.96 mmol, 1.00 equiv) and potassium hydroxide (3 g, 53.47 mmol, 5.37 equiv) in toluene (30 mL) was stirred overnight under nitrogen at rt. The resulting mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:1) to afford 0.3 g (14%) of ethyl N-(prop-2-yn-1-yl)-N-(pyrimidin-5-ylmethyl)carbamate as a light yellow oil. ¹H NMR (300 MHz, CDCl₃) δ 9.16 (s, 1H), 8.73 (s, 2H), 4.59 (s, 2H), 4.11-4.26 (m, 4H), 2.28 (t, J=2.4 Hz, 1H), 1.30 (t, J=7.2 Hz, 3H).

Step 6. Ethyl 1H,2H,3H-Pyrrolo[3,4-c]pyridine-2-carboxylate

A mixture of ethyl N-(prop-2-yn-1-yl)-N-(pyrimidin-5-ylmethyl)carbamate (1 g, 4.56 mmol, 1.00 equiv) in xylene (30 mL) was stirred under nitrogen at 150° C. for 2 days. The resulting mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1/2) to give 0.4 g (46%) of ethyl 1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxylate as a light brown crude solid. ¹H NMR (300 MHz, CDCl₃) δ 8.53-8.93 (m, 2H), 7.24 (d, J=5.1 Hz, 1H), 4.73-4.80 (m, 4H), 4.22-4.33 (m, 2H), 1.33-1.49 (m, 3H).

Step 7. 2,3-Dihydro-1H-pyrrolo[3,4-c]pyridine

A mixture of ethyl 1H,2H,3H-pyrrolo[3,4-c]pyridine-2(3H)-carboxylate (400 mg, 2.4 mmol, 1.00 equiv) and barium hydroxide (0.8 g) in water (100 mL) was stirred overnight at 120° C. The reaction mixture was cooled to rt and the solid material was collected by filtration. The residue was stirred in hot ethyl acetate (150 mL) and then filtered to remove solid material. The filtrate was concentrated under vacuum to give 0.18 g (72%) of 2,3-dihydro-1H-pyrrolo[3,4-c]pyridine as a light yellow oil. ¹H NMR (300 MHz, CDCl₃) δ 8.51 (s, 1H), 8.41-8.45 (t, J=4.8 Hz, 1H), 7.13-7.20 (m, 1H), 4.25 (s, 2H), 4.22 (s, 2H).

Intermediate 14. 2H,4H,5H,6H-Pyrrolo[3,4-c]pyrazole hydrochloride

Step 1. tert-Butyl 2H,4H,5H,6H-pyrrolo[3,4-c]pyrazole-5-carboxylate. A solution of tert-butyl 3-[(dimethylamino)methylidene]-4-oxopyrrolidine-1-carboxylate (1 g, 4.16 mmol, 1.00 equiv) and hydrazine hydrate (340 mg, 6.79 mmol, 1.63 equiv) in ethanol (10 mL) was stirred at rt for 5 h. The resulting mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5 to 1:2) to give 250 mg (29%) of tert-butyl 2H,4H,5H,6H-pyrrolo[3,4-c]pyrazole-5-carboxylate as a yellow solid. LC/MS (Method C, ESI): RT=1.30 min, m/z=210.0 [M+H]⁻.

Step 2

A solution of tert-butyl 2H,4H,5H,6H-pyrrolo[3,4-c]pyrazole-5-carboxylate (250 mg, 1.19 mmol, 1.00 equiv) in DCM (5 mL) and TFA (5 mL) was stirred overnight at rt. The resulting mixture was concentrated under vacuum and the residue was dissolved in 20 mL of concentrated HCl. The resulting mixture was concentrated under vacuum to give 200 mg of crude 2H,4H,5H,6H-pyrrolo[3,4-c]pyrazole hydrochloride as a dark red solid, LC/MS (Method C, ESI): RT=0.46 min, m/z=110.0 [M+H]⁻.

Intermediate 15. Lithium pyrazolo[1,5-b]pyridazine-5-carboxylate

Step 1. 4-Methoxypyridazine

A mixture of 3,6-dichloro-4-methoxypyridazine (30 g, 167.59 mmol, 1.00 equiv), ammonium formate (31 g, 491.63 mmol, 2.93 equiv) and 10% palladium on carbon (3 g) catalyst in MeOH (500 mL) was stirred under 1 atmosphere of hydrogen at rt overnight. The catalyst was removed by filtration and the filtrate was concentrated under vacuum. The residue was dissolved in 500 mL of DCM/MeOH (10:1). The solid material was removed by filtration. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (2:1 to 1:1) to give 15 g (81%) of 4-methoxypyridazine as a brown oil. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.1.

Step 2. Methyl 5-methoxypyrazolo[1,5-b]pyridazine-3-carboxylate

To a stirred solution of hydroxylamine-O-sulfonic acid (30.8 g, 272.57 mmol, 1.50 equiv) in water (100 mL) maintained under nitrogen at 5° C. was added a solution of potassium bicarbonate (29.1 g, 290.67 mmol, 1.60 equiv) in water (100 mL) dropwise. The resulting mixture was stirred for 10 min then a solution of 4-methoxypyridazine (20 g, 181.63 mmol, 1.00 equiv) in water (100 mL) was added. The reaction mixture was stirred at 70° C. for 5 h and then cooled back to rt. A solution of methyl prop-2-ynoate (16.8 g, 199.83 mmol, 1.10 equiv) in DCM (500 mL) followed by a solution of potassium hydroxide (17.3 g, 308.32 mmol, 1.70 equiv) in water (100 mL) were added to the reaction mixture. The resulting solution was stirred overnight at rt then extracted with 4000 mL of DCM. The organic layer was washed with 3×500 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (6:1 to 2:1) to give 1 g (3%) of methyl 5-methoxypyrazolo[1,5-b]pyridazine-3-carboxylate as a brown solid. TLC: petroleum ether:ethyl acetate=1:1, R₁=0.4.

Step 3. Pyrazolo[1,5-b]pyridazin-3-ol

A solution of methyl 5-methoxypyrazolo[1,5-b]pyridazine-3-carboxylate (2 g, 9.65 mmol, 1.00 equiv) in 40% hydrobromic acid (50 mL) was refluxed overnight. The resulting mixture was cooled to rt then concentrated under vacuum. The residue was dissolved in 50 mL of H₂O and the pH value of the solution was adjusted to 6-7 with saturated aqueous KHCO₃ solution (50 mL). The mixture was concentrated and the residue was purified on a silica gel column eluted with DCM:MeOH (10:1) to give 500 mg (38%) of pyrazolo[1,5-b]pyridazin-3-ol as a brown solid. LC/MS (Method D, ESI): RT=0.41 min, m/z=136.0 [M+H]⁺.

Step 4. Pyrazolo[1,5-b]pyridazin-3-yl trifluoromethanesulfonate

To a solution of pyrazolo[1,5-b]pyridazin-3-ol (450 mg, 3.33 mmol, 1.00 equiv) and pyridine (1.1 g, 13.91 mmol, 3.00 equiv) in DCM (20 mL) maintained under nitrogen at −5° C. was added trifluoromethanesulfonic anhydride (1.9 g, 6.73 mmol, 2.02 equiv) dropwise with stirring in 20 min. The resulting solution was stirred for another 60 min at 0° C. and then diluted with 200 mL of DCM. The mixture was washed with 3×100 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:10 to 1:5) to give 570 mg (64%) of pyrazolo[1,5-b]pyridazin-3-yl trifluoromethanesulfonate as a white solid. TLC: petroleum ether:ethyl acetate=1:1, R_(f)=0.2.

Step 5. Methyl pyrazolo[1,5-b]pyridazine-3-carboxylate

A mixture of 4aH,5H-pyrazolo[1,5-b]pyridazin-3-yl trifluoromethanesulfonate (600 mg, 2.23 mmol, 1.00 equiv), Pd(PPh₃)₂Cl₂ (300 mg, 0.43 mmol, 0.19 equiv) and pyridine (530 mg, 6.70 mmol, 3.01 equiv) in DMF (20 mL) and MeOH (5 mL) was stirred under 10 atmosphere of CO in a 50-mL pressure tank reactor overnight at 80° C. The reaction mixture was cooled to rt then diluted with 100 mL of H₂O. The resulting solution was extracted with 3×100 mL of ethyl acetate. The combined organic layers were washed with 3×100 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to yield 200 mg (51%) of methyl pyrazolo[1,5-b]pyridazine-3-carboxylate as a yellow solid. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.4.

Step 6

To a solution of methyl pyrazolo[1,5-b]pyridazine-3-carboxylate (60 mg, 0.34 mmol, 1.00 equiv) in THF (5 mL) was added a solution of LiOH (40 mg, 1.667 mmol, 1.7 equiv) in water (1 mL). The reaction mixture was stirred overnight at 50° C. and then concentrated under vacuum to give 150 mg of crude lithium pyrazolo[1,5-b]pyridazine-5-carboxylate as a dark red solid.

Intermediate 16: 2-(6-Aminopyridin-3-yl)acetic acid

Step 1, 1,3-Diethyl 2-(6-nitropyridin-3-yl)propanedioate

A mixture of 5-bromo-2-nitropyridine (2 g, 9.85 mmol, 1.00 equiv), 1,3-diethyl propanedioate (8 g, 49.95 mmol, 5.07 equiv), sodium hydride (1.2 g, 50.00 mmol, 5.07 equiv), L-proline (0.1 g) and CuI (100 mg, 0.53 mmol, 0.05 equiv) in DMF (100 mL) was stirred under nitrogen at 100° C. for 20 h. The reaction was cooled to rt and then concentrated under vacuum. The mixture was diluted with 300 mL of ethyl acetate and then washed with 3×50 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to give 2 g of crude 1,3-diethyl 2-(6-nitropyridin-3-yl)propanedioate as red oil. TLC: ethyl acetate/petroleum ether=1/1, R_(f)=0.4.

Step 2. 1,3-Diethyl 2-(6-aminopyridin-3-yl)propanedioate

A mixture of 1,3-diethyl 2-(6-nitropyridin-3-yl)propanedioate (1.5 g, 5.31 mmol, 1.00 equiv) and Raney Ni (1 g) in MeOH (30 mL) was stirred under 1 atmosphere of H₂ at rt for 2 h. The catalyst was removed by filtration and the filtrate was concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (5:1) to afford 1.3 g of crude 1,3-diethyl 2-(6-aminopyridin-3-yl)propanedioate as a yellow oil. TLC: dichloromethane/MeOH-5/1, R_(f)=0.5.

Step 3. Ethyl 2-(6-aminopyridin-3-yl)acetate

A mixture of 1,3-diethyl 2-(6-aminopyridin-3-yl)propanedioate (1.2 g, 4.76 mmol, 1.00 equiv) and lithium chloride (600 mg, 14.15 mmol, 2.98 equiv) in DMSO (10 mL) and water (1 mL) was stirred under nitrogen at 130° C. for 18 h. The reaction was cooled to rt and then diluted with 200 mL of ethyl acetate. The mixture was washed with 3×50 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/hexane (1/1) to give 200 mg (23%) of ethyl 2-(6-aminopyridin-3-yl)acetate as a light yellow oil. TLC: DCM/MeOH=5:1; R₁ 0.6.

Step 4

To a solution of ethyl 2-(6-aminopyridin-3-yl)acetate (200 mg, 1.11 mmol, 1.00 equiv) in ethanol (5 mL) was added a solution of potassium hydroxide (200 mg, 3.56 mmol, 3.21 equiv) in water (5 mL). The reaction mixture was stirred under nitrogen at rt for 11 h. The pH value of the solution was adjusted to 6 with 2 M HCl. The resulting mixture was concentrated under vacuum to give 0.5 g of crude 2-(6-aminopyridin-3-yl)acetic acid as an off-white solid. TLC: DCM/MeOH=5/1; R_(f)=0.2.

Intermediate 17. 1H,2H,3H-Pyrrolo[3,4-c]pyridin-6-amine

Step 1. 6-Chloropyridine-3-carbonyl chloride

A mixture of 6-chloropyridine-3-carboxylic acid (20 g, 126.94 mmol, 1.00 equiv), DMF (1 g, 13.68 mmol, 0.11 equiv) and thionyl chloride (20 mL) in toluene (200 mL) was stirred under nitrogen for 3 h at 80° C. The resulting solution was cooled to rt and concentrated under vacuum to give 25 g of crude 6-chloropyridine-3-carbonyl chloride as a light yellow solid.

Step 2. 6-Chloro-N,N-bis(propan-2-yl)pyridine-3-carboxamide

To a solution of 6-chloropyridine-3-carbonyl chloride (25 g, 142.05 mmol, 1.00 equiv) in DCM (500 mL) maintained under nitrogen at 0° C. was added diisopropylamine (50 g, 494.12 mmol, 3.48 equiv) dropwise with stirring. The reaction mixture was stirred for 50 min at 25° C. and then quenched with the addition of H₂O (300 mL). The organic layer was collected and the aqueous layer was extracted with 2×300 mL of DCM. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give 25 g (73%) of 6-chloro-N,N-bis(propan-2-yl)pyridine-3-carboxamide as a light yellow solid. TLC: ethyl acetate:petroleum ether=1:2. R_(f)=0.4.

Step 3. 6-Chloro-4-formyl-N,N-bis(propan-2-yl)pyridine-3-carboxamide

To a stirred solution of diisopropylamine (1 g, 9.88 mmol, 4.76 equiv) in ether (30 mL) at −50° C. maintained under nitrogen was added a 2.5M solution of n-BuLi (5 mL) in hexanes dropwise. The reaction mixture was stirred for 30 min a −50° C. then solid 6-chloro-N,N-bis(propan-2-yl)pyridine-3-carboxamide (500 mg, 2.08 mmol, 1.00 equiv) was added in a single portion. The resulting solution was stirred for 30 min at −50° C. DMF (1 mL) was then added dropwise with stirring. The reaction mixture was stirred at −50° C. for 3 h and then warmed to rt and stirred overnight. The reaction was quenched by the addition of 10% aqueous citric acid solution (30 mL) and then extracted with 2×50 mL of ether. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum to give 0.5 g of crude 6-chloro-4-formyl-N,N-bis(propan-2-yl)pyridine-3-carboxamide as a yellow solid. LC/MS (Method G, ESI): 1.40 min, m/z=269.0 [M+H]⁺.

Step 4. 6-Chloro-4-(hydroxymethyl)-N,N-bis(propan-2-yl)pyridine-3-carboxamide

A mixture of 6-chloro-4-formyl-N,N-bis(propan-2-yl)pyridine-3-carboxamide (500 mg, 1.86 mmol, 1.00 equiv) and NaBH₄ (500 mg, 13.22 mmol, 7.10 equiv) in ethanol (50 mL) was stirred for 50 min at 30° C. The reaction was then quenched by the addition of 1M HCl. The solid was removed by filtration and the filtrate was concentrated to provide 0.5 g of crude 6-chloro-4-(hydroxymethyl)-N,N-bis(propan-2-yl)pyridine-3-carboxamide as a light yellow solid. LC/MS (Method F, ESI): RT=1.25 min, m/z=271.0 [M+H]⁺.

Step 5. 6-Chloro-1H,3H-furo[3,4-c]pyridin-3-one

A mixture of 6-chloro-4-(hydroxymethyl)-N,N-bis(propan-2-yl)pyridine-3-carboxamide (2 g, 7.39 mmol, 1.00 equiv) in 6M HCl (40 mL) was stirred for 30 mm at 100° C. The reaction mixture was cooled to rt and the pH of the solution was adjusted to 8 with sodium carbonate. The mixture was extracted with 200 mL of DCM. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to yield 1 g of crude 6-chloro-1H,3H-furo[3,4-c]pyridin-3-one as a light yellow solid. LC/MS (Method R, ESI): RT=1.13 min, m/z=170.0 [M+H]⁺.

Step 6. [6-Chloro-4-(hydroxymethyl)pyridin-3-yl]methanol.

A mixture of 6-chloro-1H,3H-furo[3,4-c]pyridin-3-one (1 g, 5.90 mmol, 1.00 equiv) and NaBH₄ (0.5 g) in ethanol (50 mL) was stirred for 60 min at 25° C. The pH of the solution was adjusted to 1 with 6M HCl. The solid was removed by filtration and the filtrate was concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (20:1) to give 0.4 g (39%) of [6-chloro-4-(hydroxymethyl)pyridin-3-yl]methanol as a light yellow solid. LCMS (Method R, ESI): RT=0.95 min, m/z=174.0 [M+H]⁺.

Step 7. 2-Chloro-4,5-bis(chloromethyl)pyridine hydrochloride

A mixture of [6-chloro-4-(hydroxymethyl)pyridin-3-yl]methanol (100 mg, 0.58 mmol, 1.00 equiv) and thionyl chloride (2 mL) in DCM (20 mL) was stirred under nitrogen at rt for 1 h. The resulting mixture was concentrated under vacuum to give 0.1 g of crude 2-chloro-4,5-bis(chloromethyl)pyridine hydrochloride as a dark red solid.

Step 8. 6-Chloro-2-[(2,4-dimethoxyphenyl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine

A mixture of 2-chloro-4,5-bis(chloromethyl)pyridine hydrochloride (1 g, 4.05 mmol, 1.00 equiv), (2,4-dimethoxyphenyl) methenamine (1 g, 5.98 mmol, 1.48 equiv) and DIPEA (1 g, 7.74 mmol, 1.91 equiv) in DCM (60 mL) was stirred under nitrogen overnight at rt. The resulting mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (2:1) to give 0.9 g of crude 6-chloro-2-[(2,4-dimethoxyphenyl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine as a reddish oil. LC/MS (Method R, ESI): RT=0.94 min, m/z=305.0 [M+H]⁺.

Step 9. N,2-bis[(2,4-Dimethoxyphenyl) methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridin-6-amine.

A mixture of 6-chloro-2-[(2,4-dimethoxyphenyl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine (200 mg, 0.66 mmol, 1.00 equiv), Pd₂(dba)₃.CHCl₃ (0.1 g), t-BuONa (200 mg, 2.08 mmol, 3.17 equiv), BINAP (100 mg, 0.16 mmol, 0.24 equiv) and (2,4-dimethoxyphenyl)methanamine (400 mg, 2.39 mmol, 3.65 equiv) in toluene (20 mL) was stirred under nitrogen overnight at 80° C. The resulting solution was diluted with 20 mL of H₂O and extracted with 2×50 mL of ethyl acetate. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:1) to give 0.2 g (70%) of N,2-bis[(2,4-dimethoxyphenyl) methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridin-6-amine as a dark red solid. LC/MS (Method R, ESI): RT=0.92 min, m/z=436.0 [M+H]⁺.

Step 10

A solution of N,2-bis[(2,4-dimethoxyphenyl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridin-6-amine (300 mg, 0.69 mmol, 1.00 equiv) in TFA (20 mL) was stirred under nitrogen overnight at 90° C. The resulting mixture was concentrated under vacuum to remove most of the TFA. The pH of the residue was adjusted to 8 with saturated sodium carbonate solution. The mixture was concentrated under vacuum and the residue was dissolved in hot ethyl acetate and filtered. The filtrate was concentrated under reduced pressure to provide 0.15 g of crude 1H,2H,3H-pyrrolo[3,4-c]pyridin-6-amine as a red oil LC/MS (Method R, ESI): RT=0.18 min, z=136.0 [M+H]⁺.

Intermediate 18, 2,3-Dihydro-1H-pyrrolo[3,4-c]pyridine-d₄ hydrochloride

Step 1. 3,4-Dimethyl pyridine-3,4-dicarboxylate

To a solution of pyridine-3,4-dicarboxylic acid (35 g, 209.43 mmol, 1.00 equiv) in MeOH (250 mL) was added concentrated sulfuric acid (55 mL) dropwise with stirring at rt. The resulting solution was stirred at 100° C. overnight. The reaction mixture was cooled to rt and then concentrated under vacuum. The residue was diluted with 500 mL of H₂O and the pH of the solution was adjusted to 8 with 2M aqueous sodium carbonate solution. The resulting mixture was extracted with 3×300 mL of DCM. The combined organic layers were washed with 3×500 of brine, dried over anhydrous sodium sulfate and concentrated under vacuum to give 30 g (73%) of 3,4-dimethyl pyridine-3,4-dicarboxylate as a yellow oil. LC/MS (Method R, ESI): RT=1.23 min, m/z=195.0 [M+H]⁺.

Step 2. 3,4-bis(Hydroxymethyl)pyridine-d₄ hydrochloride

To a stirred solution of NaBD₄ (4.3 g, 102.38 mmol, 4.00 equiv) in EtOD (15 mL) maintained under nitrogen at 0° C. was added dropwise a solution of 3,4-dimethyl pyridine-3,4-dicarboxylate (5.0 g, 25.62 mmol, 1.00 equiv) in EtOD (10 mL) followed by a solution of CaCl₂ (2.5 g, 22.73 mmol, 0.90 equiv) in EtOD (20 mL) dropwise at 0° C. The reaction mixture was stirred for 3 h while the reaction temperature was maintained between 0 to 10° C. by an ice/water bath. The resulting mixture was concentrated under vacuum and the residue was dissolved in 200 mL of ethanol. The solid material was removed by filtration. The filtrate was cooled to 0° C. then hydrogen chloride gas was bubbled into the solution while keeping the reaction temperature below 5° C. with an ice/water bath. The resulting solution was stirred at 0-10° C. for 2 h. The reaction mixture was concentrated under vacuum and the residue was triturated in 100 mL of THF. The solid was collected by filtration and dried in vacuum to give 2.9 g of crude 3,4-bis(hydroxymethyl)pyridine-d₄ hydrochloride as a white solid. ¹H-NMR (300 MHz, DMSO-d₆, ppm): δ 9.00 (d, J=2.1 Hz, 1H), 8.70 (s, 1H), 8.07 (d, J=6.0 Hz, 1H).

Step 3. 2-(2,4-Dimethoxybenzyl)-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-d₄

To a solution of 3,4-bis(hydroxymethyl)pyridine-d₄ hydrochloride (3.0 g, 1.00 equiv) in DCM (80 mL) maintained under nitrogen at −5° C. was added dropwise triethylamine (10 mL, 5.00 equiv) followed by methanesulfonyl chloride (4.5 mL, 3.00 equiv) in 5 min. The reaction mixture was stirred at 0° C. for 1 h. The reaction was then quenched by the addition of 20 mL of water and the resulting mixture was extracted with 2×50 mL of DCM. The combined organic layers was washed with 1×200 mL of brine, dried over anhydrous sodium sulfate and filtered. The filtrate was cooled to 0° C. then DIPEA (5 mL, 2.0 equiv) followed by (2,4-dimethoxyphenyl)methanamine (3 mL, 1.10 equiv) was added dropwise at 0° C. within 5 min. The resulting solution was stirred at rt for 8 h. The reaction was then quenched by the addition of 20 mL of water. The resulting mixture was washed with 1×200 mL of water and 2×200 mL of brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (96/4) to give 1.4 g of crude as 2-(2,4-dimethoxybenzyl)-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-d₄ as a red oil.

Step 4

A solution of 2-(2,4-dimethoxybenzyl)-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-d₄ (700 mg, 2.04 mmol, 1.00 equiv, 80%) in CF₃COOD (5 mL) was stirred at 70° C. for 10 h. The resulting mixture was concentrated under vacuum and the residue was dissolved in 50 mL of DCM. Hydrogen chloride gas was bubbled into the stirred reaction mixture at 0° C. for 30 min. The precipitate was collected by filtration and dried in vacuum to give 600 mg of crude 2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-d₄ hydrochloride as a yellow solid. ¹H-NMR (400 MHz, D₂O, ppm): δ 8.77 (s, 1H), 8.69 (d, J=6.0 Hz, 1H), 8.00 (d, J=6.0 Hz, 1H).

II. Preparation of Example Compounds Example 1: tert-Butyl 2-[(1,3-dihydropyrrolo[3,4-c]pyridine-2-carbonylamino)methyl]-8-azaspiro[2.5]octane-8-carboxylate

Step 1. 1-[[(4-Nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate

A solution of 4-nitrophenyl chloroformate (42.5 g, 210.85 mmol, 1.00 equiv) and tert-butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate (50 mg, 0.21 mmol) in toluene (5 mL) was stirred at 120° C. for 1 h. The resulting mixture was concentrated under vacuum to give 50 mg of tert-butyl 1-[[(4-nitrophenoxycarbonyl) amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a yellow solid. LC/MS (Method K, ESI): RT=2.02 min, m/z=407.0 [M+H]⁺.

Step 2. tert-Butyl 2-[(1,3-dihydropyrrolo[3,4-c]pyridine-2-carbonylamino)methyl]-8-azaspiro[2.5]octane-8-carboxylate

A solution of tert-butyl 1-[[(4-nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate (81 mg, 0.20 mmol, 1.00 equiv) and 2,3-dihydro-1H-pyrrolo[3,4-c]pyridine (25 mg, 0.21 mmol, 1.04 equiv) in ethanol (5 mL) was stirred for 1 h at 80° C. The resulting mixture was concentrated under vacuum and the residue was purified on a silica gel column eluted with dichloromethane/methanol (10/1) to yield 8.9 mg (12%) of the title compound as an off-white solid. LC/MS (Method H, ESI): RT=1.40 min, m/z=387.0 [M+H]⁺. ¹H NMR (300 MHz, CD₃OD) δ 8.55 (s, 1H), 8.47-8.46 (d, J=5.1 Hz, 1H), 7.46-7.44 (d, J=5.1 Hz, 1H), 4.76 (s, 2H), 3.64-3.54 (m, 2H), 3.37 (s, 2H), 3.27-3.20 (m, 2H), 1.70-1.63 (m, 1H), 1.46 (s, 11H), 1.25-1.19 (m, 1H), 1.07-1.05 (m, 1H), 0.62-0.53 (m, 1H), 0.32-0.21 (m, 1H).

Example 6: N-[[8-(3,3-dimethylbutanoyl)-8-azaspiro[2.5]octan-2-yl]methyl]-1H-pyrrolo[3,2-c]pyridine-2-carboxamide

Step 1. tert-Butyl 2-[(1H-pyrrolo[3,2-c]pyridine-2-carbonylamino)methyl]-8-azaspiro[2.5]octane-8-carboxylate

A solution of tert-butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate (1750 mg, 7.28 mmol, 1.00 equiv), 1H-pyrrolo[3,2-c]pyridine-2-carboxylic acid (1299 mg, 8.01 mmol, 1.10 equiv), EDCI (2786 mg, 14.53 mmol, 2.00 equiv), triethylamine (2946 mg, 29.11 mmol, 4.00 equiv), and HOBt (1181 mg, 8.74 mmol, 1.20 equiv) in DMF (30 mL) was stirred overnight at room temperature. The resulting solution was diluted with 100 mL of water and extracted with 3×100 mL of ethyl acetate. The combined organic layers were washed with 3×200 mL of brine, dried over anhydrous sodium sulfate, and concentrated under vacuum to afford 2.3 g (82%) of the title compound as a red oil. LC/MS (Method C, ESI): RT=1.29 min, in m/z=385.0 [M+H]⁺.

Step 2. N-(8-azaspiro[2.5]octan-2-ylmethyl)-1H-pyrrolo[3,2-c]pyridine-2-carboxamide trifluoroacetate salt

A solution of tert-butyl 2-[(1H-pyrrolo[3,2-c]pyridine-2-carbonylamino)methyl]-8-azaspiro[2.5]octane-8-carboxylate (3.2 g, 8.32 mmol, 1.00 equiv) in TFA (10 mL) and dichloromethane (10 mL) was stirred for 3 h at room temperature. The resulting mixture was concentrated under vacuum to give 4 g of crude title product as a brown oil. LC/MS (Method E, ESI): RT=0.96 min, m/z=285.0 [M+H]⁺.

Step 3

To a solution of N-(8-azaspiro[2.5]octan-2-ylmethyl)-1H-pyrrolo[3,2-c]pyridine-2-carboxamide trifluoroacetate salt (179 mg, 0.44 mmol, 1.00 equiv) and triethylamine (136 mg, 1.32 mmol, 3.01 equiv) in dichloromethane (5 mL) at 0° C. was added 3,3-dimethylbutanoyl chloride (60 mg, 0.44 mmol, 1.00 equiv) dropwise with stirring. The resulting solution was stirred for 1 h at room temperature. The reaction mixture was diluted with 20 mL of dichloromethane, washed with 2×10 mL of brine, then dried over anhydrous sodium sulfate and concentrated under vacuum. The crude product (110 mg) was purified by preparative HPLC (Instrument, Waters 2767-2; Column, sunfire-C18; mobile phase, water with NH₄HCO₃ (1 g/L) and CH₃CN (25% CH₃CN up to 57% in 10 min); Detector, UV 254 nm) to give 2.3 mg (1%) of the title compound as a white solid. LC/MS (Method H, ESI): RT=1.95 min, m/z=383.0 [M+H]⁺, ¹H NMR (400 Hz, CDCl₃) δ 9.02 (s, 1H), 8.42-8.41 (d, J=4.8 Hz, 1H), 7.54 (m, 1H), 7.01 (s, 1H), 6.48 (m, 1H), 4.10-4.09 (m, 1H), 3.67-3.32 (m, 5H), 2.35-2.25 (m, 2H), 1.63-1.50 (m, 2H), 1.28-1.22 (m, 1H), 1.07 (s, 11H), 0.71 (s, 1H), 0.39 (s, 1H).

Example 150, N-([6-[2-(3-methyloxetan-3-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H-pyrrolo[3,2-c]pyridine-2-carboxamide

Step 1. Ethyl 2-(oxetan-3-ylidene)acetate

A solution of oxetan-3-one (2.0 g, 27.75 mmol, 1.00 equiv) and (ethoxycarbonylmethylene)triphenylphosphorane (10.2 g, 29.28 mmol, 1.10 equiv) in DCM (40 mL) was stirred at 0° C. for 30 min. The reaction mixture was concentrated under vacuum and the residue was triturated in 200 mL of petroleum ether. The solid material was removed by filtration. The filtrate was concentrated under vacuum to give 3.3 g of crude ethyl 2-(oxetan-3-ylidene)acetate as a colorless liquid. LC/MS (Method A, ESI): RT=1.32 min, m/z=143.0 [M+H]⁺.

Step 2. Ethyl 2-(3-methyloxetan-3-yl)acetate

To a solution of ethyl 2-(oxetan-3-ylidene)acetate (1.5 g, 8.55 mmol, 1.00 equiv, 81%) and CuI (163 mg, 0.86 mmol, 0.10 equiv) in THF (10 mL) maintained under nitrogen was added a solution of chlorotrimethylsilane (1.85 g, 17.03 mmol, 2.00 equiv) in THF (30 mL). The reaction mixture was stirred at rt for 15 min and then cooled to −15° C. A 1.4 N solution of methylmagnesium chloride (24.5 mL, 4.00 equiv) in THF was added dropwise with stirring in 10 min. The resulting solution was stirred at 25° C. for 1 h and then quenched by the addition of 20 mL of saturated aqueous NH₄Cl solution. The mixture was concentrated under vacuum. The residue was redissolved in 100 mL of DCM then washed with 1×100 mL of water and 2×100 mL of brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give 600 mg of crude ethyl 2-(3-methyloxetan-3-yl)acetate as a red oil.

Step 3. 2-(3-Methyloxetan-3-yl)acetic acid

To a solution of ethyl 2-(3-methyloxetan-3-yl)acetate (500 mg, 3.16 mmol, 1.00 equiv) in MeOH (15 mL) was added a 2M aqueous sodium hydroxide (5 mL) solution. The mixture was stirred at 40° C. for 12 h and then cooled to rt. The reaction mixture was concentrated under vacuum. The residue was dissolved in 50 mL of water and then washed with 3×50 mL of DCM. The aqueous layer was collected and the pH value of the solution was adjusted to 5 with 1M HCl. The resulting mixture was concentrated under vacuum and the residue was dissolved with 50 mL of MeOH. The solid material was removed by filtration. The filtrate was concentrated under vacuum to give 260 mg of crude 2-(3-methyloxetan-3-yl)acetic acid as a red solid. ¹H NMR (400 MHz, D₂O-d₄, ppm): δ 4.63 (s, 2H), 4.33 (s, 2H), 2.19 (s, 2H), 1.27 (s, 3H).

Step 4

A solution of 2-(3-methyloxetan-3-yl)acetic acid (66 mg, 0.51 mmol, 2.00 equiv), EDCI (72 mg, 0.38 mmol, 1.50 equiv), HOBt (51 mg, 0.38 mmol, 1.50 equiv) and DIPEA (162 mg, 1.25 mmol, 5.00 equiv) in DMF (10 mL) was stirred at rt for 1 h. N-[6-Azaspiro[2.5]octan-1-ylmethyl]-1H-pyrrolo[3,2-c]pyridine-2-carboxamide dihydrochloride (90 mg, 0.25 mmol, 1.00 equiv) was then added and the resulting solution was stirred at 25° C. for 12 h. The reaction mixture was concentrated under vacuum. The residue was dissolved in 100 mL of DCM and then washed with 2×100 mL of brine. The organic layer was concentrated under vacuum and the residue was purified by Prep-HPLC (SHIMADZU-PDA (LC-08): Column, XSelect CSH Prep C18 OBD Column, 5 um, 19*150 mm, mobile phase, water with 0.025% ammonium carbonate and CH₃CN (8% CH₃CN up to 22.0% in 12 mm, up to 95.0% in 1 min, hold 95.0% in 1 min, down to 8.0% in 2 min); Detector, UV 254/220 nm) to give 13.5 mg (13%) of N-([6-[2-(3-methyloxetan-3-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H-pyrrolo[3,2-c]pyridine-2-carboxamide as a white solid. LC/MS (Method K, ESI): RT=1.88 min, m/z=397.1 [M+H]⁺. ¹H-NMR (400 MHz, CDCl₃, ppm): δ 9.03 (s, 1H), 8.42 (d, J=5.6 Hz, 1H), 7.39 (d, J=6.0 Hz, 1H), 6.98 (s, 1H), 6.40 (s, 1H), 4.60-4.59 (m, 2H), 4.48-4.46 (m, 2H), 3.99-3.97 (m, 1H), 3.65-3.60 (m, 2H), 3.46-3.31 (m, 3H), 2.73 (s, 2H), 1.76-1.63 (m, 4H), 1.47 (s, 3H), 1.28-1.23 (m, 1H), 1.10-1.08 (m, 1H), 0.74-0.72 (m, 1H), 0.42-0.39 (m, 1H).

Example 159. N-[[6-(p-tolylcarbamoyl)-6-azaspiro[2.5]octan-2-yl]methyl]furo[2,3-c]pyridine-2-carboxamide

A solution of N-(6-azaspiro[2.5]octan-2-ylmethyl)furo[2,3-c]pyridine-2-carboxamide; 2,2,2-trifluoroacetic acid (60 mg, 0.15 mmol, 1.00 equiv), 1-isocyanato-4-methyl-benzene (20 mg, 0.15 mmol, 1.00 equiv) and triethylamine (65 uL, 0.45 mmol, 3.00 equiv) in 10% DMF in DCM (2.0 mL) was stirred at 50° C. for 2 h. The reaction mixture was concentrated under vacuum and the crude product was purified by Prep-HPLC (Column, Sunfire C18 19×150; mobile phase, CH₃CN:NH₄CO₃/H₂O (10 mmol/L)=5%-85%, 10 min: Detector, UV 254 nm) to give 16 mg (25%) of N-[[6-(p-tolylcarbamoyl)-6-azaspiro[2.5]octan-2-yl]methyl]furo[2,3-c]pyridine-2-carboxamide as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.05 (s, 1H), 9.05-9.00 (m, 1H), 8.47 (d, J=5.3 Hz, 1H), 8.33 (s, 1H), 7.82 (d, J=5.2, 1.0 Hz, 1H), 7.61 (s, 1H), 7.31 (d, 2H), 7.01 (d, J=8.2 Hz, 2H), 3.67-3.53 (m, 2H), 3.46-3.25 (m, 2H), 2.21 (s, 3H), 1.70-1.58 (m, 1H), 1.50-1.37 (m, 2H), 1.24-1.14 (m, 1H), 1.12-0.98 (m, 1H), 0.60-0.52 (m, 1H), 0.31 (t, J=4.8 Hz, 1H).

Example 174. N-([6-[2-(3-hydroxy-3-methylcyclobutyl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)furo[2,3-c]pyridine-2-carboxamide

Step 1. tert-Butyl 2-(2,2-dichloro-3-oxocyclobutyl)acetate

A mixture of tert-butyl but-3-enoate (10 g, 70.33 mmol, 1.00 equiv) in ether (250 mL), trichloroacetyl chloride (34 g, 186.98 mmol, 2.66 equiv) and Zn—Cu (13 g) in ethylene glycol dimethyl ether (40 mL) was stirred under nitrogen at rt for 48 h. The reaction mixture was filtered to remove the solid material. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:10) to yield 21 g of tert-butyl 2-(2,2-dichloro-3-oxocyclobutyl)acetate as a brown liquid. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.6.

Step 2. tert-Butyl 2-(3-oxocyclobutyl)acetate

A mixture of tert-butyl 2-(2,2-dichloro-3-oxocyclobutyl)acetate (500 mg, 1.98 mmol, 1.00 equiv) and zinc (635 mg, 9.71 mmol, 4.91 equiv) in a saturated NH₄Cl solution in MeOH (20 mL) was stirred at rt overnight. The mixture was filtered to remove the solid material. The filtrate was concentrated under vacuum t give 300 mg (82%) of tert-butyl 2-(3-oxocyclobutyl)acetate as a light yellow oil. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.5.

Step 3. tert-Butyl 2-(3-hydroxy-3-methylcyclobutyl)acetate

To a stirred solution of tert-butyl 2-(3-oxocyclobutyl)acetate (300 mg, 1.63 mmol, 1.00 equiv) in THF (50 mL) maintained under nitrogen at 0° C. was added dropwise a 3M solution of CH₃MgBr (0.8 mL) in THF. The reaction mixture was stirred at rt for 1 h and then quenched by the addition of 20 mL of saturated NH₄Cl solution. The organic layer was collected and the aqueous layer was extracted with 50 mL of DCM. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to give 270 mg (83%) of tert-butyl 2-(3-hydroxy-3-methylcyclobutyl)acetate as a light yellow oil.

Step 4. 2-(3-Hydroxy-3-methylcyclobutyl)acetic acid

To a solution of tert-butyl 2-(3-hydroxy-3-methylcyclobutyl)acetate (270 mg, 1.35 mmol, 1.00 equiv) in DCM (50 mL) was added TFA (1 mL). The resulting solution was stirred overnight at room temperature then concentrated under vacuum to give 240 mg of crude 2-(3-hydroxy-3-methylcyclobutyl)acetic acid as brown oil.

Step 5

A solution of 2-(3-hydroxy-3-methylcyclobutyl)acetic acid (200 mg, 1.39 mmol, 5.58 equiv), EDCI (265 mg, 1.38 mmol, 5.56 equiv), HOBt (187 mg, 1.38 mmol, 5.57 equiv) and DIPEA (1 mL) in DMF (10 mL) was stirred for 10 min at rt. N-[6-Azaspiro[2.5]octan-1-ylmethyl]furo[2,3-c]pyridine-2-carboxamide hydrochloride (80 mg, 0.25 mmol, 1.00 equiv) was then added. The reaction mixture was stirred overnight at rt and then concentrated under vacuum. The residue was dissolved in 100 mL of DCM and the resulting solution was washed with 50 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (20:1). The partially purified product (110 mg) was repurified by Prep-HPLC (Column, Xbridge RP18 19*150; mobile phase, CH₃CN:NH₄CO₃/H₂O (10 mmol/L), 5%-19% over 15 min; Detector, UV 254 nm) to give 19.6 mg (19%) of N-([6-[2-(3-hydroxy-3-methylcyclobutyl) acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)furo[2,3-c]pyridine-2-carboxamide as a white solid. LC/MS (Method I, ESI): RT=1.66 min, m/z=412.0 [M+H]⁺. ¹H-NMR (300 MHz, DMSO-d₆, ppm): δ 9.06 (t, 2H), 8.48 (d, J=5.2 Hz, 2H), 7.81 (d, J=4.4 Hz, 1H), 7.61 (s, 1H), 4.75 (s, 1H), 3.73-3.53 (m, 1H), 3.49-3.32 (m, 1H), 2.50-2.21 (m, 3H), 2.03-2.02 (m, 3H), 1.64 (s, 3H), 1.44-1.33 (m, 2H), 1.19-1.13 (m, 3H), 1.10-1.03 (m, 1H), 0.56-0.53 (m, 1H), 0.32-0.29 (m, 1H).

Example 274. tert-Butyl 2-[(4,6-dihydro-1H-pyrrolo[3,4-c]pyrazole-5-carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate

Step 1. tert-Butyl 1-[[(4-nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate

To a stirred mixture of tert-butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate oxalic acid salt (200 mg, 0.61 mmol, 1.00 equiv) and 4-nitrophenyl chloroformate (122 mg, 0.61 mmol, 1.00 equiv) in DCM (10 mL) at 0-5° C. was added triethylamine (184 mg, 1.82 mmol, 3.00 equiv) dropwise. The resulting solution was stirred at 0-5° C. for another 2 h. The resulting mixture was concentrated under vacuum to give 400 mg of crude tert-butyl 1-[[(4-nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a yellow solid. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.3.

Step 2

A solution of tert-butyl 1-[[(4-nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate (250 mg, 0.62 mmol, 1.00 equiv), 1H,4H,5H,6H-pyrrolo[3,4-c]pyrazole hydrochloride (90 mg, 0.62 mmol, 1.00 equiv) and triethylamine (187 mg, 1.85 mmol, 3.00 equiv) in ethanol (5 mL) was stirred at 78° C. for 2 h. The resulting mixture was warmed to rt and concentrated under vacuum. The residue was dissolved in 50 mL of DCM and the resulting mixture was washed with 3×50 mL of brine. The organic layer was concentrated under vacuum and the residue was purified by Prep-HPLC (Waters-1; Column, Sunfire C18 19*150; mobile phase A: 0.2% aqueous NH₄HCO₃, phase B: CH₃CN, gradient: 10% to 43% B over 10 min, up to 100% B in 13 min, Detector, UV 254 nm) to give 33.7 mg (15%) of tert-butyl 1-[[([1H,4H,5H,6H-pyrrolo[3,4-c]pyrazol-5-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a white solid LC/MS (Method Q, EST): RT=1.49 min, m/z=376.2 [M+H]⁺. ¹H-NMR (300 MHz, CDCl₃, ppm): δ 7.36 (s, 1H), 4.51 (s, 4H), 4.31 (s, 1H), 3.61 (br s, 2H), 3.34-3.22 (m, 4H), 1.67-1.60 (m, 1H), 1.49 (s, 1H), 1.46 (s, 9H), 1.39 (s, 1H), 1.18-1.14 (m, 1H), 0.97-0.92 (m, 1H), 0.60-0.57 (m, 1H), 0.29-0.21 (m, 1H).

Example 275. N-([6-[2-(1,4-dimethylpiperidin-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)furo[2,3-c]pyridine-2-carboxamide

Step 1. Ethyl 2-(1-methylpiperidin-4-ylidene)acetate

A mixture of 1-methylpiperidin-4-one (5 g, 44.19 mmol, 1.00 equiv) and (ethoxycarbonylmethylene)triphenylphosphorane (17 g, 48.80 mmol, 1.00 equiv) in DCM (200 mL) was stirred at 0-5° C. for 3 h. The resulting mixture was concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:10) to give 1 g (12%) of ethyl 2-(1-methylpiperidin-4-ylidene)acetate as a colorless oil. LC/MS (Method Q, ESI): RT=035 min, m/z=184.0 [M+H]⁺.

Step 2. Ethyl 2-(1,4-dimethylpiperidin-4-yl)acetate

A solution of ethyl 2-(1-methylpiperidin-4-ylidene)acetate (1 g, 5.46 mmol, 1.00 equiv), CuI (1.2 g, 6.30 mmol, 1.15 equiv) and (CH₃)₃SiCl (2.3 g, 21.3 mmol, 3.90 equiv) in THF (50 mL) was stirred under nitrogen at rt for 2 h. The reaction mixture was cooled to −30° C. and a 3M solution of MeMgBr (11 mL, 33.0 mmol, 6.04 equiv) in THF was added dropwise with stirring. The reaction mixture was stirred at −30° C. for 30 min and then slowly warmed to rt and then stirred overnight. The reaction was quenched by the addition of 50 mL of water and the resulting solution was extracted with 4×50 mL of ethyl acetate. The combined organic layers was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to give 800 mg of crude ethyl 2-(1,4-dimethylpiperidin-4-yl)acetate as a light yellow oil. LC/MS (Method Q, ESI): RT=0.26 min, m/z=200.0 [M+H]⁺.

Step 3. 2-(1,4-Dimethylpiperidin-4-yl)acetic acid

To a solution of ethyl 2-(1,4-dimethylpiperidin-4-yl)acetate (800 mg, 4.01 mmol, 1.00 equiv) in THF (10 mL) was added a 10% aqueous sodium hydroxide solution (6 mL). The resulting solution was stirred overnight at 65° C. The reaction mixture was cooled to rt and the pH value of the solution was adjusted to 7 with 5% HCl. The resulting mixture was extracted with 3×50 mL of DCM. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum to give 1.6 g of crude 2-(1,4-dimethylpiperidin-4-yl)acetic acid as a light yellow solid. LC/MS (Method R, ESI): RT=0.26 min, m/z=172.0 [M+H]⁺.

Step 4. tert-Butyl 1-([furo[2 3-c]pyridin-2-ylformamido]methyl)-6-azaspiro[2.5]octane-6-carboxylate

A solution of furo[2,3-c]pyridine-2-carboxylic acid (510 mg, 3.13 mmol, 1.50 equiv), EDCI (517 mg, 2.70 mmol, 1.30 equiv), HOBt (365 mg, 2.70 mmol, 1.30 equiv) and DIPEA (2 mL) in DMF (20 mL) was stirred at rt for 10 min. tert-Butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate (500 mg, 2.08 mmol, 1.00 equiv) was then added and the resulting solution was stirred overnight at rt. The reaction mixture was diluted with 200 mL of ethyl acetate and washed with 100 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:1) to give 600 mg (75%) of tert-butyl 1-([furo[2,3-c]pyridin-2-ylformamido]methyl)-6-azaspiro[2.5]octane-6-carboxylate as a light yellow oil. LC/MS (Method J, ESI): RT=1.23 min, m/z=386.0[M+H]⁺.

Step 5. N-[6-Azaspiro[2.5]octan-1-ylmethyl]furo[2,3-c]pyridine-2-carboxamide hydrochloride

A solution of tert-butyl 1-([furo[2,3-c]pyridin-2-ylformamido]methyl)-6-azaspiro[2.5]octane-6-carboxylate (1 g, 2.59 mmol, 1.00 equiv) in 1M solution of hydrogen chloride in MeOH (100 mL) was stirred at rt for 3 h. The reaction mixture was concentrated under vacuum to give 0.8 g (96%) of N-[6-azaspiro[2.5]octan-1-ylmethyl]furo[2,3-c]pyridine-2-carboxamide hydrochloride as a white solid. LC/MS (Method Q, ESI): RT=0.38 min, m/z=286.0[M+H]⁺.

Step 6

A solution of 2-(1,4-dimethylpiperidin-4-yl)acetic acid (1.6 g (crude solid), 9.34 mmol, 11.16 equiv), EDCI (300 mg, 1.56 mmol, 1.87 equiv), HOBt (250 mg, 1.85 mmol, 2.21 equiv) and DIPEA (2 mL) in DMF (30 mL) was stirred at rt for 10 min. N-[6-Azaspiro[2,5]octan-1-ylmethyl]furo[2,3-c]pyridine-2-carboxamide dihydrochloride (300 mg, 0.84 mmol, 1.00 equiv) was then added and the resulting solution was stirred overnight at rt. The solid material was removed by filtration. The filtrate was concentrated under reduced pressure and the residue was purified by Prep-HPLC (Column: Sunfire C18 19*150: mobile phase, CH₃CN:NH₄CO₃/H₂O (10 mmol/L), 15%-60%, 10 min; Detector, UV 254 nm) to give 43 mg (12%) of N-([6-[2-(1,4-dimethylpiperidin-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)furo[2,3-c]pyridine-2-carboxamide as a light yellow solid. LC/MS (Method A, ESI): RT=1.70 min, m/z=439.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 9.04 (s, 2H), 8.48 (d, J=5.1 Hz, 1H), 7.80 (d, J=5.4 Hz, 1H), 7.60 (s, 1H), 3.67-3.56 (m, 2H), 3.39-3.32 (m, 2H), 2.29-2.24 (m, 5H), 2.11-2.09 (m, 6H), 1.59-1.52 (m, 3H), 1.50-1.22 (m, 4H), 1.21-1.16 (m, 1H), 1.06-1.01 (m, 1H), 0.94 (d, J=5.4 Hz, 3H), 0.60-0.50 (m, 1H), 0.31-0.29 (m, 1H).

Example 339. N-[[6-[4-(4-Methylpiperazin-1-yl)benzoyl]-6-azaspiro[2.5]octan-2-yl]methyl]furo[2,3-c]pyridine-2-carboxamide

Step 1. Ethyl 4-(4-methylpiperazin-1-yl)benzoate

A solution of ethyl 4-fluorobenzoate (2 g, 11.89 mmol, 1.00 equiv), 1-methylpiperazine (1.6 g, 15.97 mmol, 1.34 equiv) and potassium carbonate (2.2 g, 15.92 mmol, 1.34 equiv) in DMF (30 mL) was stirred at 80° C. for 2 days. The resulting solution was diluted with 150 mL of H₂O and the pH value of the solution was adjusted to 1 with 10% HCl. The resulting solution was washed with 100 mL of ethyl acetate. The aqueous layer was collected and the pH value of the solution was adjusted to 10 with sodium carbonate. The resulting solution was extracted with 2×100 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to give 1.3 g (44%) of ethyl 4-(4-methylpiperazin-1-yl)benzoate as a white solid. TLC: DCM:MeOH=10:1, R_(f)=0.5.

Step 2. 4-(4-Methylpiperazin-1-yl)benzoic acid

To a solution of ethyl 4-(4-methylpiperazin-1-yl)benzoate (1.3 g, 5.24 mmol, 1.00 equiv) in THF (10 mL) was added a 10% aqueous sodium hydroxide solution (8 mL). The resulting solution was stirred at 70° C. overnight. After cooling to rt, the pH value of the solution was adjusted to 5 with 5% HCl. The resulting solution was extracted with 3×100 mL of DCM. The combined organic layers was and concentrated under vacuum to give 2.2 g of crude 4-(4-methylpiperazin-1-yl)benzoic acid as a white solid. LC/MS (Method C, ESI): RT=0.54 min, m/z=221[M+H]⁺.

Step 3. N-[(6-[[4-(4-Methylpiperazin-1-yl)phenyl]carbonyl]-6-azaspiro[2.5]octan-1-yl)methyl]furo[2,3-c]pyridine-2-carboxamide

A solution of 4-(4-methylpiperazin-1-yl)benzoic acid (200 mg, 0.91 mmol, 1.00 equiv), EDCI (200 mg, 1.04 mmol, 1.15 equiv), HOBt (150 mg, 1.11 mmol, 1.22 equiv) and DIPEA (2 mL) in DMF (10 mL) was stirred at rt for 10 min. N-[6-Azaspiro[2.5]octan-1-ylmethyl]furo[2,3-c]pyridine-2-carboxamide dihydrochloride (100 mg, 0.28 mmol, 0.31 equiv) was then added and the resulting solution was stirred at rt overnight. The reaction mixture was concentrated under vacuum and the crude product was purified by Prep-HPLC (Column, Sunfire C18 19×150; mobile phase, CH₃CN: NH₄CO₃/H₂O (10 mmol/L)=15%-60%, 10 min; Detector, UV 254 nm) to give 40 mg (9%) of N-[(6-[[4-(4-methylpiperazin-1-yl)phenyl] carbonyl]-6-azaspiro[2.5]octan-1-yl)methyl]furo[2,3-c]pyridine-2-carboxamide as an off-white solid. LC/MS (Method F, ESI): RT=1.12 min, m/z=488.3[M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 9.07-9.05 (m, 2H), 8.48 (d, J=5.4 Hz, 1H), 7.82-7.80 (m, 1H), 7.61 (s, 1H), 7.26 (d, J=8.7 Hz, 2H), 6.94 (d, J=8.7 Hz, 2H), 3.62-3.58 (m, 2H), 3.39-3.25 (m, 3H), 3.25-3.17 (m, 4H), 2.49-2.41 (m, 4H), 2.21 (s, 3H), 1.68-1.62 (m, 1H), 1.46-1.43 (m, 2H), 1.23-1.18 (m, 1H), 1.04-1.00 (m, 1H), 0.58-0.56 (m, 1H), 0.35-0.29 (m, 1H).

Example 383. tert-Butyl 2-[(pyrazolo[1,5-b]pyridazine-5-carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate

A solution of lithium pyrazolo[1,5-b]pyridazine-5-carboxylate (90 mg, 0.53 mmol, 1.00 equiv), tert-butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate trifluoroacetic acid salt (193 mg, 0.54 mmol, 1.01 equiv), EDCI (372 mg, 1.94 mmol, 3.66 equiv), HOBt (99 mg, 0.73 mmol, 1.38 equiv) and triethylamine (246 mg, 2.43 mmol, 4.6 equiv) in DMF (5 mL) was stirred at rt for 3 h. The reaction was then quenched by the addition of 100 mL of H₂O and the resulting solution was extracted with 3×100 mL of ethyl acetate. The combined organic layers were washed with 3×100 mL of brine, dried over sodium sulfate and concentrated under vacuum. The residue was first purified on a silica gel column eluted with DCM:MeOH (30:1). The partially purified product was repurified by Prep-HPLC (Waters-1; Column, XBridge C18 19*150; mobile phase A: 0.2% aqueous NH₄HCO₃; mobile phase B: CH₃CN; gradient, 10 to 43% CH₃CN in 10 min, up to 100% in 13 min; Detector, UV 254 nm) to give 17.2 mg (9%) of tert-butyl 1-([pyrazolo[1,5-b]pyridazin-3-ylformamido]methyl)-6-azaspiro[2.5]octane-6-carboxylate as a white solid. LC/MS (Method S, ESI): RT=1.48 min, m/z=386.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.77 (t, J=2.4 Hz, 1H), 8.74 (s, 1H), 8.73 (s, 1H), 8.18 (d, J=2.4 Hz, 1H), 7.05 (d, J=2.7 Hz, 1H), 3.59-3.43 (m, 2H), 3.41-3.35 (m, 2H), 3.25-3.17 (m, 2H), 1.67-1.54 (m, 1H), 1.46-1.31 (m, 11H), 1.19-1.09 (m, 1H), 1.05-0.95 (m, 1H), 0.59-0.50 (m, 1H), 0.31-0.25 (m, 1H).

Example 394. N-[[6-[2-(6-Amino-3-pyridyl)acetyl]-6-azaspiro[2.5]octan-2-yl]methyl]-1,3-dihydropyrrolo[3,4-c]pyridine-2-carboxamide

A solution of 2-(6-aminopyridin-3-yl)acetic acid (150 mg, 0.99 mmol, 1.00 equiv), N-6-azaspiro[2.5]octan-1-ylmethyl-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide (350 mg, 1.22 mmol, 1.20 equiv), DIPEA (400 mg, 3.00 equiv), EDCI (230 g, 1.20 mol, 1.20 equiv) and HOBt (170 mg, 1.26 mmol, 1.20 equiv) in DMF (20 mL) was stirred at rt for 20 h. The resulting mixture was concentrated under vacuum and the residue was first purified on a silica gel column eluted with DCM/MeOH (5:1). The partially purified product (300 mg) was repurified by Flash-Prep-HPLC (IntelFlash-1: Column, silica gel; mobile phase, 15 to 45% CH₃CN in within 30 min; Detector, UV 254 nm) to give 93 mg (22%) of N-([6-[2-(6-aminopyridin-3-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide as an off-white solid. LC/MS (Method C, ESI): RT=1.01 min, m/z=421.1 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.57 (s, 1H), 8.47 (d, J=4.8 Hz, 1H), 7.74 (s, 1H), 7.39 (d, J=4.8 Hz, 1H), 7.21 (dd, J=6.0 Hz, 2.4 Hz, 1H), 6.44-6.36 (m, 2H), 5.72 (s, 2H), 4.62 (d, J=2.7 Hz, 4H), 3.65-3.54 (m, 4H), 3.40-3.33 (m, 1H), 3.18-3.09 (m, 3H), 1.54-1.48 (m, 1.32-0.95 (m, 4H), 0.55-0.45 (m, 1H), 0.25-0.15 (m, 1H).

Example 399. N-[[6-[2-(4-Methyltetrahydropyran-4-yl)acetyl]-6-azaspiro[2.5]octan-2-yl]methyl]-1,3-dihydropyrrolo[3,4-c]pyridine-2-carboxamide

Step 1. Ethyl 2-(oxan-4-ylidene)acetate

A solution of oxan-4-one (2 g, 19.98 mmol, 1.00 equiv) and (ethoxycarbonylmethylene)triphenylphosphorane (8 g, 22.96 mmol, 1.15 equiv) in acetonitrile (50 mL) was stirred at 70° C. for 16 h. The resulting mixture was cooled to rt and concentrated. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to give 1.9 g (56%) of ethyl 2-(oxan-4-ylidene)acetate as a colorless solid. TLC: petroleum ether:ethyl acetate=1:2, R_(f)=0.5.

Step 2. Ethyl 2-(4-methyloxan-4-yl)acetate

To a stirred solution of CuI (2.9 g, 15.23 mmol, 3.24 equiv) in ether (50 mL) maintained under nitrogen at 0° C. was added a 1.6 M solution of methyllithium (20 mL, 32 mmol, 6.8 equiv) in ether dropwise. The resulting solution was stirred at 0″C for 10 min and the ether solvent was removed from the reaction vessel under vacuum at 0° C. DCM (50 mL) was then added to the residue and the reaction was cooled to −78° C. Chlorotrimethylsilane (1.9 g, 17.6 mmol, 3.7 equiv) was then added dropwise followed by a solution of ethyl 2-(oxan-4-ylidene)acetate (800 mg, 4.70 mmol, 1.00 equiv) in DCM (20 mL) to the reaction mixture at −78° C. The resulting solution was stirred for another 30 min at −78° C. and then at 0° C. for 2 h. The reaction quenched by the addition of 50 mL of water. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give 750 mg (86%) of ethyl 2-(4-methyloxan-4-yl)acetate as a colorless oil.

Step 3. 2-(4-Methyloxan-4-yl)acetic acid

To a solution of ethyl 2-(4-methyloxan-4-yl)acetate (750 mg, 4.03 mmol, 1.00 equiv) in ethanol (20 mL) at 0° C. was added dropwise a solution of sodium hydroxide (817 mg, 5.00 equiv) in water (4 mL) with stirring. The resulting solution was stirred overnight at rt and then concentrated to remove ethanol. The resulting solution was diluted with 10 mL of H₂O and washed with 3×20 mL of ether The aqueous layer was collected and the pH value of the solution was adjusted to 4-5 with 2N HCl. The aqueous layer was extracted with 4×15 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated to give 600 mg (94%) of 2-(4-methyloxan-4-yl)acetic acid as yellow oil. LC/MS (Method S, ESI): RT=0.5 min, m/z=159 [M+H]⁺.

Step 4

A solution of 2-(4-methyloxan-4-yl)acetic acid (100 mg, 0.63 mmol, 1.26 equiv), DIPEA (1 mL), HOBt (85 mg, 0.63 mmol, 1.26 equiv), and EDCI (120 mg, 0.63 mmol, 1.25 equiv) in DMF (4 mL) was stirred at rt for 10 min. N-[6-Azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide dihydrochloride (180 mg, 0.50 mmol, 1.00 equiv) was then added and the reaction mixture was stirred overnight at rt. The resulting solution was diluted with 100 mL of DCM and then washed with 60 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate and concentrated. The residue was purified on a silica gel column eluted with DCM/MeOH (20:1) to give 110 mg (51%) of N-([6-[2-(4-methyloxan-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide as a light yellow solid. LC/MS (Method F, ESI): RT=1.19 min, m/z=428.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.55 (s, 1H), 8.46 (d, J=5.1 Hz, 1H), 7.38 (d, J=5.1 Hz, 1H), 6.42 (t, J=4.9 Hz, 1H), 4.61 (d, 4H), 3.69-3.31 (m, 8H), 3.15-3.08 (m, 2H), 2.31 (s, 2H), 1.62-1.49 (m, 3H), 1.45-1.25 (m, 4H), 1.21-1.05 (m, 1H), 1.04-0.89 (m, 4H), 0.55-0.51 (m, 1H), 0.25-0.15 (m, 1H).

Example 403. N-[[6-[2-[4-Methyl-1-(2,2,2-trifluoroethyl)-4-piperidyl]acetyl]-6-azaspiro[2.5]octan-2-yl]methyl]-1,3-dihydropyrrolo[3,4-c]pyridine-2-carboxamide

Step 1. tert-Butyl 4-methyl-4-[2-oxo-2-(1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octan-6-yl)ethyl]piperidine-1-carboxylate. A solution of 2-[1-[(tert-butoxy)carbonyl]-4-methylpiperidin-4-yl]acetic acid (450 mg, 1.75 mmol, 2.09 equiv), EDCI (340 mg), HOBt (250 mg, 1.85 mmol, 2.22 equiv) and DIPEA (2 mL) in DMF (15 mL) was stirred at rt for 10 min. N-[6-Azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide dihydrochloride (300 mg, 0.83 mmol, 1.00 equiv) was then added and the reaction mixture was stirred overnight at rt. The resulting solution was diluted with 200 mL of ethyl acetate and washed with 100 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate and concentrated. The residue was purified on a silica gel column eluted with DCM/MeOH (20:1) to yield 210 mg (48%) of tert-butyl 4-methyl-4-[2-oxo-2-(1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octan-6-yl)ethyl]piperidine-1-carboxylate as a light yellow oil. TLC: DCM:MeOH=10:1, R_(f)=0.5.

Step 2. N-([6-[2-(4-Methylpiperidin-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide hydrochloride

Hydrogen chloride gas was bubbled into a solution of tert-butyl 4-methyl-4-[2-oxo-2-(1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octan-6-yl)ethyl]piperidine-1-carboxylate (210 mg, 0.40 mmol, 1.00 equiv) in 1,4-dioxane (20 mL) at 0° C. for 20 min. The resulting solution was stirred at rt for 1 h and then concentrated under vacuum to give 220 mg of crude N-([6-[2-(4-methylpiperidin-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide hydrochloride as a light yellow solid. LC/MS (Method F, ESI): RT=0.89 min, m/z=426.0[M+H]⁺.

Step 3

To a solution of N-([6-[2-(4-methylpiperidin-4-yl)acetyl]-6-azaspiro[2.5]octan-1-yl]methyl)-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide dihydrochloride (220 mg, 0.44 mmol, 1.00 equiv) in DMF (10 mL) at rt was added 2,2,2-trifluoroethyl trifluoromethanesulfonate (140 mg, 0.60 mmol, 1.37 equiv) followed by DIPEA (2 mL). The reaction mixture was stirred at room temperature for 2 h and then diluted with 200 mL of ethyl acetate. The resulting mixture was washed with 100 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified on a silica gel column eluted with dichloromethane/methanol (20:1) to give 35.2 mg (16%) of N-[(6-[2-[4-methyl-1-(2,2,2-trifluoroethyl)piperidin-4-yl]acetyl]-6-azaspiro[2.5]octan-1-yl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide as a white solid. LC/MS (Method I, ESI): RT=1.15 min, m/z=508.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.56 (s, 1H), 8.46 (d, J=4.5 Hz, 1H), 7.39 (d, J=4.8 Hz, 1H), 6.43 (s, 1H), 4.62 (s, 4H), 3.65-3.58 (m, 2H), 3.48-3.33 (m, 3H), 3.20-3.01 (m, 4H), 2.59-2.50 (m, 3H), 2.27 (s, 2H), 1.59-1.56 (m, 3H), 1.39-1.30 (m, 3H), 1.01-0.96 (m, 4H). 0.49-0.45 (m, 1H), 0.25-0.23 (m, 1H).

Example 405. N-[[6-[4-(1-Methyl-4-piperidyl)benzoyl]-6-azaspiro[2.5]octan-2-yl]methyl]-1,3-dihydropyrrolo[3,4-c]pyridine-2-carboxamide

Step 1. tert-Butyl 4-[4-(ethoxycarbonyl)phenyl]-1,2,3,6-tetrahydropyridine-1-carboxylate

A mixture of ethyl 4-bromobenzoate (1 g, 4.37 mmol, 1.00 equiv), tert-butyl 4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1,2,3,6-tetrahydropyridine-1-carboxylate (1.4 g, 4.53 mmol, 1.04 equiv), Pd(PPh₃)₄ (0.2 g), and potassium carbonate (800 mg, 5.79 mmol, 1.33 equiv) in 1,4-dioxane (10 mL) was stirred under nitrogen in a 20-mL sealed tube at 100° C. overnight. The reaction mixture was cooled to rt then diluted with 120 mL of ethyl acetate. The solid material was removed by filtration and the filtrate was washed with 100 mL of water. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:20) to give 1 g (69%) of tert-butyl 4-[4-(ethoxycarbonyl)phenyl]-1,2,3,6-tetrahydropyridine-1-carboxylate as a white solid. TLC: petroleum ether:ethyl acetate=5:1, R_(t)=0.3.

Step 2. tert-Butyl 4-[4-(ethoxycarbonyl)phenyl]piperidine-1-carboxylate

A mixture of tert-butyl 4-[4-(ethoxycarbonyl)phenyl]-1,2,3,6-tetrahydropyridine-1-carboxylate (1 g, 3.02 mmol, 1.00 equiv) and 10% palladium on carbon (0.5 g) catalyst in ethanol (50 mL) was stirred under 1 atmosphere of H₂ at rt for 2 h. The catalyst was removed by filtration. The filtrate was concentrated under vacuum to give 1.2 g of crude tert-butyl 4-[4-(ethoxycarbonyl)phenyl]piperidine-1-carboxylate as a gray colored oil. TLC: petroleum ether:ethyl acetate=5:1, R_(f)=0.4.

Step 3. Ethyl 4-(piperidin-4-yl)benzoate hydrochloride

Thionyl chloride (2 mL) was added dropwise with stirring at rt to ethanol (50 mL), tert-Butyl 4-[4-(ethoxycarbonyl)phenyl]piperidine-1-carboxylate (1 g, 3.00 mmol, 1.00 equiv) was then added to the reaction mixture and the resulting solution was stirred at rt for 1 h. The reaction mixture was concentrated under vacuum to give 0.8 g (99%) of ethyl 4-(piperidin-4-yl)benzoate hydrochloride as an off-white solid. LC/MS (Method Q, ESI): RT=1.03 min, m/z=233 [M+H]⁺.

Step 4. Methyl 4-(1-methylpiperidin-4-yl)benzoate

A solution of methyl 4-(piperidin-4-yl)benzoate hydrochloride (800 mg, 3.13 mmol, 1.00 equiv) and paraformaldehyde (180 mg) in ethanol (50 mL) and water (10 mL) was stirred at 60° C. for 1 h. Sodium cyanoborohydride (400 mg) and acetic acid (0.1 mL) were then added. The resulting solution was stirred overnight at 60° C. The reaction mixture was cooled to rt and concentrated under vacuum. The resulting solution was diluted with 50 mL of H₂O and extracted with 3×50 mL of DCM. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (10:1) to give 700 mg (96%) of methyl 4-(1-methylpiperidin-4-yl)benzoate as a colorless oil. LC/MS (Method I, ESI): RT=1.12 min, m/z=247 [M+H]⁺.

Step 5. 4-(1-Methylpiperidin-4-yl)benzoic acid

To a solution of ethyl 4-(1-methylpiperidin-4-yl)benzoate (700 mg, 2.83 mmol, 1.00 equiv) in ethanol (30 mL) was added a solution of sodium hydroxide (340 mg, 8.50 mmol, 3.00 equiv) in water (5 mL). The reaction mixture was stirred overnight at 60° C. and then cooled tort. The pH of the solution was adjusted to 7 with 5% HCl and then extracted with 3×50 mL of DCM. The combined organic layers were dried over anhydrous sodium sulfate then concentrated under vacuum to give 1 g of crude 4-(1-methylpiperidin-4-yl)benzoic acid as a white solid. LC/MS (Method I, ESI): RT=0.93 min, m/z=220 [M+H]⁺.

Step 6

A solution of 4-(1-methylpiperidin-4-yl)benzoic acid (131 mg, 0.60 mmol, 2.15 equiv), EDCI (80 mg, 0.42 mmol, 1.50 equiv), HOBt (57 mg, 0.42 mmol, 1.52 equiv) and DIPEA (1 mL) in DMF (6 mL) was stirred at rt for 10 min. N-[6-Azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide dihydrochloride (100 mg, 0.28 mmol, 1.00 equiv) was then added and the reaction mixture was stirred overnight at rt. The resulting solution was diluted with 30 mL of H₂O then extracted with 3×50 mL of DCM. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum. The crude product was purified by Prep-HPLC (Column, Sunfire C18 19*150; mobile phase, CH₃CN:NH₃/H₂O (5 mL/10 L), 15%-70%, 10 min; Detector, UV 254 nm) to give 23.7 mg (17%) of N-[(6-[[4-(1-methylpiperidin-4-yl)phenyl]carbonyl]-6-azaspiro[2.5]octan-1-yl)methyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide as a white solid. LC/MS (Method I, ESI): RT=1.25 min, m/z=488.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.56 (s, 1H), 8.46 (d, J=4.5 Hz, 1H), 7.38 (d, J=3.6 Hz, 1H), 7.29 (s, 4H), 6.43 (s, 1H), 4.63 (s, 4H), 3.76-3.74 (m, 1H), 3.51-3.33 (m, 3H), 3.20-3.12 (m, 2H), 2.83 (d, J=5.1 Hz, 2H), 2.44-2.39 (m, 1H), 2.18 (s, 3H), 1.98-1.91 (m, 2H), 1.70-1.62 (m, 5H), 1.54-1.24 (m, 3H), 1.01-0.96 (m, 1H), 0.54-0.49 (m, 1H), 0.24-0.21 (m, 1H).

Example 406, tert-Butyl 2-[[(6-amino-1,3-dihydropyrrolo[3,4-c]pyridine-2-carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate

A solution of tert-butyl 1-[[(4-nitrophenoxycarbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate (200 mg, 0.49 mmol, 1.00 equiv), 1H,2H,3H-pyrrolo[3,4-c]pyridin-6-amine (80 mg, 0.59 mmol, 1.20 equiv) and DIPEA (200 mg, 1.55 mmol, 3.14 equiv) in DCM (50 mL) was stirred at rt for 2 h. The reaction mixture was concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (5:1) to give 0.113 g (57%) of tert-butyl 1-[[([6-amino-1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a light yellow solid. LC/MS (Method K, ESI): RT=1.65 min, m/z=402.2 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 7.94 (s, 1H), 6.59 (s, 1H), 5.25 (s, 2H), 4.64-4.52 (m, 6H), 3.61 (s, 2H), 3.27 (d, J=8.1 Hz, 5H), 1.65 (d, J=8.4 Hz, 1H), 7.94 (s, 9H), 1.14-1.09 (m, 1H), 0.95-0.83 (m, 1H), 0.59-0.55 (m, 1H), 0.26-0.24 (m, 1H).

Example 409. (3-Methyloxetan-3-yl) 2-[[(1,1,3,3-tetradeuteriopyrrolo[3,4-c]pyridine-2-carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate

Step 1. tert-Butyl 1-[({1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl}carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate-d₄. To a solution of tert-butyl 1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate (1.0 g, 4.16 mmol, 1.00 equiv) in DCM (20 mL) at 0° C. was added 4-nitrophenyl carbonochloridate (830 mg, 4.12 mmol, 1.00 equiv) and triethylamine (0.6 mL, 4.6 mmol, 1.10 equiv). The resulting solution was stirred at rt for 2 h. A solution of triethylamine (1.5 mL) in DCM (80 mL) followed by 2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-d₄ hydrochloride (700 mg, crude) were added. The reaction mixture was stirred at 25° C. for 3 h then washed with 1×100 mL of sodium bicarbonate, 1×100 mL of water and 1×100 mL of brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (95/5) to give 500 mg of tert-butyl 1-[({1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl}carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate-d₄ as a yellow solid. LC/MS (Method I, ESI): RT=1.17 min, m/z=391.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆ ppm): δ 8.47 (s, 1H), 8.46 (d, J=4.5 Hz, 1H), 7.38 (d, J=4.2 Hz, 1H), 6.34 (s, 1H), 3.51-3.41 (m, 2H), 3.22-3.02 (m, 4H), 1.62-1.55 (m, 1H), 1.42-1.35 (m, 11H), 1.22-1.08 (m, 1H), 0.99-0.92 (m, 1H), 0.51-0.39 (m, 1H), 0.22-0.17 (m, 1H).

Step 2. N-{6-Azaspiro[2.5]octan-1-ylmethyl}-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide-d₄

To a solution of tert-butyl 1-[({1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl}carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate-d₄ (500 mg, 1.00 equiv) in DCM (15 mL) was added CF₃COOD (2 mL) dropwise at rt. The resulting solution was stirred at rt for 1 h then concentrated under vacuum. The residue was dissolved in 10 mL of MeOH. The pH of the solution was adjusted to 8 with saturated aqueous sodium carbonate solution. The resulting mixture was concentrated under vacuum to give 1.5 g of crude N-{6-azaspiro[2.5]octan-1-ylmethyl}-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide-d₄ as a yellow solid. LC/MS (Method I, ESI): RT=0.82 min, m/z=291.0 [M+H]⁺.

Step 3

A solution of N-{6-azaspiro[2.5]octan-1-ylmethyl}pyrrolo[3,4-c]pyridine-2-carboxamide-d₄ (500 mg, crude), 3-methyloxetan-3-yl 4-nitrophenyl carbonate (136 mg, 0.54 mmol, 1.2 equiv) and triethylamine (91 mg, 0.90 mmol, 2.0 equiv) in DCM (1.5 mL) was stirred at rt for 5 h. The reaction mixture was diluted with 50 mL of DCM and then washed with 1×50 mL of sodium bicarbonate, 1×50 mL of water and 1×50 mL of brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was first purified on a silica gel column eluted with DCM/MeOH (95/5). The partially purified product (80 mg) was repurified by Prep-HPLC (1#-Pre-HPLC-005 (Waters): Column, SunFire Prep C18 OBD Column, 5 um, 19*150 mm; mobile phase, water with 10 mmol NH₄HCO₃ and CH₃CN (15.0% CH₃CN up to 34.0% in 10 min, up to 95.0% in 2 min, down to 15.0% in 2 min); Detector, UV 254/220 nm) to give 47 mg of 3-methyloxetan-3-yl 1-[({1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl}carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate-d₄ as a white solid. LC/MS (Method I, ESI): RT=1.39 min, m/z=405.0 [M+H]⁺. ¹H NMR (300 MHz, DMSO-d₆, ppm): δ 8.57 (s, 1H), 8.46 (d, J=5.1 Hz, 1H), 7.38 (d, J=5.1 Hz, 1H), 6.42 (t, J=5.1 Hz, 1H), 4.64-4.58 (m, 2H), 4.42-4.36 (m, 2H), 3.50-3.47 (m, 2H), 3.31-3.28 (m, 2H), 3.16-3.06 (m, 2H), 1.62 (s, 3H), 1.64-1.56 (m, 1H), 1.40-1.36 (m, 2H), 1.20-1.17 (m, 1H), 1.00-0.96 (m, 1H), 0.49-0.47 (m, 1H), 0.24-0.20 (m, 1H).

Example 419. (3-Methyloxetan-3-yl) (2S)-2-[(1,3-dihydropyrrolo[3,4-c]pyridine-2-carbonylamino)methyl]-6-azaspiro[2.5]octane-6-carboxylate

Step 1. tert-Butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate

A mixture of tert-butyl 4-oxopiperidine-1-carboxylate (300 g, 1.51 mol. 1.00 equiv), ethyl 2-(diethoxyphosphoryl)acetate (405 g, 1.81 mol, 1.20 equiv) and potassium carbonate (314 g, 2.26 mol, 1.50 equiv) in DMF (4.5 L) was stirred overnight at 80° C. The reaction was cooled to rt and then quenched by the addition of 5 L of water/ice. The precipitate was collected by filtration and air-dried to give 252 g (62%) of tert-butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate as a white solid. TLC: ethyl acetate/petroleum ether=1:2, R_(f)=0.6.

Step 2. 6-tert-Butyl 1-ethyl 6-azaspiro[2.5]octane-1,6-dicarboxylate

A solution of trimethylsulfoxonium iodide (618 g, 2.81 mol, 3.00 equiv) and t-BuOK (315 g, 2.81 mol, 3.00 equiv) in DMSO (5 L) was stirred at rt for 1 h. tert-Butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate (252 g, 935.63 mmol, 1.00 equiv) was then added in several portions. The reaction mixture was stirred at rt overnight and then quenched by the addition of 10 L of saturated NH₄Cl solution. The resulting mixture was extracted with 3×3 L of ethyl acetate. The organic combined layers were washed with 2×1.5 L of brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1/10) to give 147 g of 6-tert-butyl 1-ethyl 6-azaspiro[2.5]octane-1,6-dicarboxylate as yellow oil. TLC: ethyl acetate/petroleum ether=1:2, R_(f)=0.5.

Step 3. 6-[(tert-Butoxy)carbonyl]-6-azaspiro[2.5]octane-1-carboxylic acid

To a stirred solution of 6-tert-butyl 1-ethyl 6-azaspiro[2.5]octane-1,6-dicarboxylate (147 g, 1.00 equiv) in ethanol (1 L) at 0° C. was added dropwise a solution of sodium hydroxide (104 g, 2.60 mol, 5.00 equiv) in water (200 mL). The resulting solution was stirred at rt overnight. The reaction mixture was concentrated to remove the excess ethanol. Water (2 L) was added and the mixture was washed with 3×500 mL of ethyl acetate. The aqueous layer was collected and the pH of the solution was adjusted to 5-6 with 1M HCl. The resulting mixture was extracted with 4×600 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give 129 g of crude 6-[(tert-butoxy)carbonyl]-6-azaspiro[2.5]octane-1-carboxylic acid as a white solid. TLC: DCM/MeOH=5:1, R_(f)=0.1.

Step 4. tert-Butyl (1S)-1-[[(1S)-1-phenylethyl]carbamoyl]-6-azaspiro[2.5]octane-6-carboxylate

To a stirred solution of 6-[(tert-butoxy)carbonyl]-6-azaspiro[2.5]octane-1-carboxylic acid (129 g, 505.27 mmol, 1.00 equiv), DIPEA (196 g, 1.52 mol, 6.02 equiv) and (S)-(−)-1-phenylethanamine (87 g, 717.94 mmol, 1.10 equiv) in DMF (2 L) 0° C. was added O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (231 g, 607.89 mmol, 1.20 equiv) in several portions. The resulting solution was stirred at rt overnight and then was quenched by the addition of 4.5 L of water/ice. The resulting mixture was extracted with 3×2 L of ethyl acetate. The combined organic layers were washed with 2×800 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1/4) to give 83.15 g (46%) of tert-butyl 1-[[(1S)-1-phenylethyl]carbamoyl]-6-azaspiro[2.5]octane-6-carboxylate as a mixture of diastereomers as a white solid. LC/MS (Method I, ESI): RT₁=4.63 min, RT₂=4.73 min, m/z=359.1 [M+H] The resulting mixture of diastereomers was separated by chiral supercritical fluid chromatography (Column: 3×25 cm, 5 um Chiralpak AD; Mobile phase A: CO2; Mobile phase B; 0.1% NH4OH in MeOH; Isocratic conditions: 87:13 A:B; Flow rate: 200 g/min; UV: 220 nm; Back pressure: 100 bar; Column temperature: 40° C.). The first eluting diastereomer was carried forward into the next step.

Step 5. (1S)—N-[(1S)-1-Phenylethyl]-6-azaspiro[2.5]octane-1-carboxamide

Hydrogen chloride gas was bubbled into a solution of tert-butyl (1S)-1-[[(1S)-1-phenylethyl]carbamoyl]-6-azaspiro[2.5]octane-6-carboxylate (20 g, 55.79 mmol, 1.00 equiv) in MeOH (200 mL) at 0° C. for 30 min. The resulting solution was stirred overnight at rt and then concentrated under vacuum. The residue was diluted with 100 mL of H₂O and the pH of the solution was adjusted to 12 with 2N sodium hydroxide solution. The resulting mixture was extracted with 3×100 mL of DCM. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum to give 15 g of (1S)—N-[(1S)-1-phenylethyl]-6-azaspiro[2.5]octane-1-carboxamide as a light yellow solid. LC/MS (Method I, ESI): RT=1.03 min, m/z=259.0 [M+H]⁺.

Step 6. tert-Butyl (1S)-1-([[(1S)-1-phenylethyl]amino]methyl)-6-azaspiro[2.5]octane-6-carboxylate

To a stirred solution of (1S)—N-[(1S)-1-phenylethyl]-6-azaspiro[2.5]octane-1-carboxamide (8 g, 30.96 mmol, 1.00 equiv) in THF (800 mL) maintained under nitrogen at rt was added a 1 M solution of borane in THF (100 mL, 100 mmol, 3.3 equiv) dropwise. The resulting solution was refluxed overnight. The resulting mixture was concentrated under vacuum then water (50 mL) was added to the residue. The pH of the solution was adjusted to 1 with 5% HCl (5%). The resulting solution was stirred at reflux for 4 h. The reaction mixture was cooled to rt and the pH of the solution was adjusted to 12 with a 10% sodium hydroxide solution. The solution was cooled to 0° C. then a solution of di-tert-butyl dicarbonate (6.7 g, 30.70 mmol, 0.68 equiv) in 20 mL of THF was added dropwise with stirring. The reaction mixture was stirred overnight at rt. The resulting mixture was extracted with 2×200 mL of ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:3) to give 2.9 g (19%) of tert-butyl (1S)-1-([[(1S)-1-phenylethyl]amino]methyl)-6-azaspiro[2.5]octane-6-carboxylate as light brown oil. TLC: DCM:MeOH=10:1. R_(f)=0.3.

Step 7. tert-Butyl (1S)-1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate

A mixture of tert-butyl (1S)-1-([[(1S)-1-phenylethyl]amino]methyl)-6-azaspiro[2.5]octane-6-carboxylate (700 mg, 2.03 mmol, 1.00 equiv) and Pd(OH)₂ (100 mg) in MeOH (30 mL) was stirred under 5 atmosphere of H₂ in a 50-mL pressure reactor overnight at rt. The catalyst was removed by filtration. The filtrate was concentrated under vacuum to afford 400 mg (82%) of tert-butyl (1S)-1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate as a light yellow oil. LC/MS (Method F, ESI): RT=1.25 min, m/z=241.0 [M+H]⁺.

Step 8. tert-Butyl (1S)-1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate

A solution of tert-butyl (1S)-1-(aminomethyl)-6-azaspiro[2.5]octane-6-carboxylate (5 g, 20.80 mmol, 1.00 equiv), 4-nitrophenyl chloroformate (4.4 g, 21.83 mmol, 1.05 equiv) and DIPEA (10 mL) in THF (200 mL) was stirred overnight at rt. 1H,2H,3H-Pyrrolo[3,4-c]pyridine dihydrochloride (4.4 g, 22.79 mmol, 9.24 equiv) was then added and the reaction mixture was stirred overnight at rt. The resulting mixture was concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (20/1) to give 2.3 g of tert-butyl (1S)-1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a light yellow solid. TLC: DCM:MeOH=10:1, R_(f)=0.4.

Step 9. N-[(1S)-6-Azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide hydrochloride

A solution of tert-butyl (1S)-1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl) amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate (2.3 g, 5.95 mmol, 1.00 equiv) in a saturated hydrogen chloride in MeOH solution (100 mL) was stirred at rt for 2 h. The resulting mixture was concentrated under vacuum to yield 1.7 g of crude N-[(1S)-6-azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide hydrochloride as a brown solid.

Step 10. 3-Methyloxetan-3-yl 4-nitrophenyl carbonate

To a stirred solution of oxetan-3-one (9 g, 124.89 mmol, 1.00 equiv) in THF (200 mL) maintained under nitrogen at −50° C. was added dropwise a 1.6M solution of methyllithium in ether (150 mL, 240 mmol, 1.9 equiv). The reaction mixture was warmed to 0° C. and stirred for 2 h. A solution of 4-nitrophenyl chloroformate (26 g, 128.99 mmol, 1.03 equiv) in THF (100 mL) was then added dropwise at 0° C. The resulting solution was stirred for another 2 h at rt after the addition was completed. The reaction was then quenched by the addition of 200 mL of water. The resulting mixture was extracted with 2×200 mL of ethyl acetate. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:5) to give 4.5 g (14%) of 3-methyloxetan-3-yl 4-nitrophenyl carbonate as a white solid. TLC: petroleum ether:ethyl acetate=2:1, R_(f)=0.6.

Step 11

A solution of N-[(1S)-6-azaspiro[2.5]octan-1-ylmethyl]-1H,2H,3H-pyrrolo[3,4-c]pyridine-2-carboxamide hydrochloride (1.7 g, 5.27 mmol, 1.00 equiv), 3-methyloxetan-3-yl 4-nitrophenyl carbonate (1.7 g, 6.71 mmol, 1.27 equiv) and DIPEA (2 mL) in ethanol (50 mL) was stirred overnight at rt. The resulting mixture was concentrated under vacuum. The residue was dissolved in 150 mL of DCM and then washed with 100 mL of H₂O. The organic layer was dried over anhydrous sodium sulfate then concentrated under vacuum. The residue was purified on a silica gel column eluted with DCM/MeOH (20/1) to give 1.43 g (68%) of 3-methyloxetan-3-yl (1S)-1-[[([1H,2H,3H-pyrrolo[3,4-c]pyridin-2-yl]carbonyl)amino]methyl]-6-azaspiro[2.5]octane-6-carboxylate as a white solid. LC/MS (Method I, ESI): RT=1.24 min, m/z=401.1 [M+H]⁺. ¹H-NMR (300 MHz, DMSO-d₆, ppm): δ 8.56 (s, 1H), 8.47 (d, J=5.1 Hz, 1H), 7.39 (d, J=5.1 Hz, 2H), 6.42 (t, J=5.2 Hz, 1H), 4.63-4.59 (m, 6H), 4.38 (d, J=7.5 Hz, 2H), 3.48 (s, 2H), 3.31 (s, 2H), 3.12 (t, J=6.0 Hz, 2H), 1.62 (s, 3H), 1.59-1.55 (m, 1H), 1.42-1.39 (m, 2H), 1.37-1.34 (m, 1H), 1.21-1.17 (m, 1H), 1.01-0.96 (m, 1H), 0.54-0.48 (m, 1H), 0.27-0.21 (m, 1H).

Additional example compounds were prepared using methods analogous to those described above. Particular example compounds were prepared using methods analogous to those indicated for the Example numbers listed below:

Ex. Method of Example No. 22 6 23 6 24 6 25 1 26 339 27 339 28 339 29 339 30 339 31 339 32 339 33 339 34 339 35 339 36 339 37 339 38 339 39 339 40 6 41 383 42 383 43 339 44 339 45 1 and 6 46 6 47 1 and 6 48 1 49 1 50 339 51 339 52 339 53 339 54 339 55 339 56 339 57 339 58 339 59 339 60 339 61 339 62 339 63 339 64 339 65 339 66 339 67 339 68 339 69 339 70 339 71 339 72 339 73 339 74 339 75 339 76 339 77 339 78 339 79 339 80 339 81 339 82 339 83 339 84 339 85 339 86 339 87 339 88 339 89 339 90 339 91 339 92 339 93 339 94 339 95 339 96 339 97 339 98 339 99 339 100 339 101 339 102 339 103 339 104 339 105 339 106 339 107 339 108 339 109 339 110 339 111 339 112 339 113 339 114 339 115 339 116 339 117 339 118 339 119 339 120 339 121 339 122 339 123 339 124 339 125 339 126 339 127 339 128 339 129 339 130 339 131 339 132 339 133 339 134 339 135 339 136 339 137 339 138 339 139 339 140 339 141 339 142 339 143 339 144 339 145 339 146 339 147 339 148 6 149 6 151 1 152 339 153 339 154 339 155 339 156 339 157 159 158 159 160 159 161 159 162 159 163 159 164 159 165 159 166 159 167 159 168 159 169 159 170 159 171 159 172 159 173 159 175 150 176 1 and 6 177 1 and 6 178 1 and 6 179 339 180 339 181 339 182 159 183 159 184 159 185 159 186 159 187 159 188 1 and 6 189 1 and 6 190 1 and 6 191 6 192 6 193 1 194 1 195 150 196 6 197 6 198 6 199 6 200 1 201 1 and 6 202 1 and 6 203 6 204 419 205 419 206 6 207 1 and 6 208 6 209 6 210 6 211 6 212 1 213 6 214 6 215 419 216 6 218 1 219 150 220 150 221 150 222 339 223 339 228 1 229 6 230 1 and 6 231 339 232 339 233 339 234 339 235 339 236 339 237 339 238 339 239 339 240 339 241 339 242 339 243 339 244 339 245 339 246 339 247 339 248 339 249 339 250 339 251 339 252 339 253 339 254 339 255 339 256 339 257 339 258 339 259 339 260 339 261 339 262 339 263 339 264 339 265 339 266 339 267 339 268 339 269 339 270 339 271 339 272 339 273 339 275 6 276 174 277 6 278 6 279 1 and 6 280 339 281 339 282 339 283 339 284 339 285 6 286 6 287 6 288 6 289 6 290 6 291 6 292 1 and 6 293 6 294 339 295 339 296 339 297 339 298 339 299 339 300 339 301 339 302 339 303 339 304 339 305 339 306 339 307 339 308 339 309 339 310 339 311 339 312 339 313 339 314 339 315 339 316 339 317 339 318 339 319 339 320 339 321 339 322 339 323 339 324 339 325 339 326 339 327 339 328 339 329 339 330 339 331 339 332 339 333 339 334 339 335 339 336 339 337 339 338 339 340 339 341 339 343 6 344 6 345 6 346 1 and 6 347 1 and 6 348 6 350 1 351 1 352 1 and 6 353 1 and 6 354 1 and 6 355 1 and 6 356 6 357 1 and 6 358 6 359 6 360 1 and 6 361 1 362 339 363 339 364 6 365 1 and 6 366 1 and 6 367 409 368 6 369 6 370 6 371 6 372 6 373 6 375 1 376 1 and 6 377 6 378 6 379 6 381 6 382 1 384 339 385 339 387 6 388 1 389 6 392 1 393 1 and 6 395 1 396 1 and 6 397 6 398 1 and 6 399 6 400 174 401 6 402 6 404 1 and 6 407 1 and 6 408 409 410 409 411 6 413 419 414 419 415 1 and 6 416 1 and 6 417 1 and 6 418 1 and 6

Additional examples were prepared using methods analogous to those described above.

Analytical Characterization:

Each of the specifically exemplified compounds described herein was prepared using the methods analogous to those described above, and were analyzed by LC/MS. Data for each compound, along with the LC/MS method used to generate the data, is provided in Table 1 (NA=not available).

TABLE 1 LC/MS Data for Example Compounds. Retention time Ex. (mm) m z Method 2 1.63 402.0 E 3 3.43 386.1 B 4 1.60 386.0 E 5 3.60 385.1 B 7 3.44 403.0 C 8 3.19 385.2 L 9 1.40 395.0 H 10 1.16 397.0 H 11 1.43 398.2 C 12 1.24 355.0 H 13 2.45 425.2 C 14 1.21 377.0 C 15 4.25 386.0 L 16 2.39 327.3 J 17 1.27 363.0 A 18 2.23 285.1 M 19 2.41 286.1 M 20 1.71 341.2 C 21 2.62 399.0 A 22 3.59 385.1 B 23 2.63 386.1 I 24 1.37 383.2 C 25 1.07 387.3 O 26 2.59 394.2 T 27 3.60 410.2 T 28 3.80 482.2 T 29 4.19 384.3 T 30 2.83 426.3 T 31 4.06 429.2 T 32 3.79 368.2 T 33 2.99 397.2 T 34 3.66 409.2 T 35 3.18 411.3 T 36 3.66 412.3 T 37 3.61 398.2 T 38 3.93 400.2 T 39 3.02 405.2 T 40 1.04 482.3 Q 41 4.46 385.2 T 42 4.45 385.3 T 43 4.50 386.2 T 44 4.49 386.2 T 45 1.35 385 I 46 1.95 369 B 47 1.31 405 I 48 4.36 387.3 T 49 4.35 387.3 T 50 3.48 406.2 T 51 3.57 413.3 T 52 3.94 412.3 T 53 3.15 411.3 T 54 3.85 413.2 T 55 3.48 413.2 T 56 3.39 411.2 T 57 3.45 411.2 T 58 3.91 390.2 T 59 3.54 384.2 T 60 3.63 398.2 T 61 3.58 384.2 T 62 3.18 371.2 T 63 3.64 436.3 T 64 3.34 426.3 T 65 3.04 427.3 T 66 3.41 432.2 T 67 3.53 422.3 T 68 3.44 425.3 T 69 3.87 468.2 T 70 3.60 457.2 T 71 3.79 475.2 T 72 3.70 447.2 T 73 3.79 475.2 T 74 3.65 475.2 T 75 2.95 427.3 T 76 3.54 461.2 T 77 3.88 459.2 T 78 3.36 440.3 T 79 3.36 440.3 T 80 3.46 446.2 T 81 3.81 472.2 T 82 3.52 439.3 T 83 3.81 472.2 T 84 3.79 483.2 T 85 3.87 523.2 T 86 3.29 502.3 T 87 3.41 502.3 T 88 3.54 502.3 T 89 2.91 440.3 T 90 3.70 439.3 T 91 2.79 426.3 T 92 3.81 468.2 T 93 3.85 468.2 T 94 3.52 448.2 T 95 2.91 454.3 T 96 3.84 486.3 T 97 3.12 391.2 T 98 3.56 391.2 T 99 3.49 381.2 T 100 3.19 381.2 T 101 2.97 380.2 T 102 3.41 392.2 T 103 3.21 391.2 T 104 3.44 380.2 T 105 2.98 394.2 T 106 3.43 394.2 T 107 3.43 394.2 T 108 3.62 394.2 T 109 3.59 394.2 T 110 3.33 392.2 T 111 3.39 392.2 T 112 3.46 392.2 T 113 3.32 392.2 T 114 3.49 394.2 T 115 3.58 408.2 T 116 3.76 408.2 T 117 3.72 395.2 T 118 4.09 396.2 T 119 3.12 405.2 T 120 3.10 405.2 T 121 3.15 405.2 T 122 3.65 406.2 T 123 3.85 420.2 T 124 3.74 422.2 T 125 3.72 409.2 T 126 3.65 408.2 T 127 3.77 416.2 T 128 3.70 409.2 T 129 3.37 476.3 T 130 3.73 354.2 T 131 4.30 462.2 T 132 3.75 461.2 T 133 3.51 448.2 T 134 3.42 448.2 T 135 3.70 448.2 T 136 3.91 423.2 T 137 3.88 422.2 T 138 3.73 422.2 T 139 3.65 395.2 T 140 3.80 436.3 T 141 3.37 380.2 T 142 3.82 489.3 T 143 2.95 413.3 T 144 3.73 439.3 T 145 3.37 411.2 T 146 3.27 461.3 T 147 3.74 489.3 T 148 1.29 453 I 149 1.74 425 I 150 1.88 397.1 K 151 0.97 373.2 S 152 4.10 429.2 T 153 3.44 372.2 T 154 4.64 536.2 T 155 3.38 413.3 T 156 2.97 405.1 T 157 4.07 430.2 T 158 4.24 433.3 T 159 4.20 419.2 T 160 4.03 419.2 T 161 4.08 437.2 T 162 4.24 433.3 T 163 4.09 437.2 T 164 4.13 449.2 T 165 4.05 449.2 T 166 4.09 437.2 T 167 4.03 449.2 T 168 4.51 489.2 T 169 4.71 463.3 T 170 4.31 453.2 T 171 4.25 453.2 T 172 3.47 357.2 T 173 4.53 489.2 T 174 1.66 412 I 175 2.58 399 B 176 1.67 406.1 B 177 2.32 406.2 K 178 2.1 429.9 C 179 3.71 457.2 T 180 3.13 408.2 T 181 3.48 422.2 T 182 3.83 385.3 T 183 3.59 371.2 T 184 4.35 425.3 T 185 3.63 371.2 T 186 4.12 411.3 T 187 3.98 405.2 T 188 1.09 454.1 C 189 1.9 371.1 B 190 1.61 406.1 B 191 1.52 340.1 K 192 1.21 359.2 F 193 1.55 399.2 G 194 1.57 344.1 G 195 1.39 398.1 K 196 2.05 411.3 F 197 1.6 425 C 198 0.87 414.2 F 199 1.43 418.9 C 200 1.49 401.2 I 201 1.33 441.3 F 202 3.49 473.1 B 203 1.31 384.2 I 204 3.10 396.6 T 205 4.13 430.2 T 206 1.33 428 I 207 1.88 430 I 208 1.92 406.2 F 209 1.04 441.9 C 210 1.29 420 I 211 1.98 440.9 C 212 2.04 386.3 F 213 4.11 383.3 T 214 4.12 383.3 T 215 3.83 402.2 T 216 1.32 428 I 218 2.12 439.2 C 219 1.27 413.2 L 220 1.06 423.3 F 221 1.21 395.2 R 222 3.74 450.3 T 223 4.12 502.3 T 228 1.41 399.2 Q 229 3.24 428.2 B 230 2.24 441 I 231 3.42 405.2 T 232 3.10 405.2 T 233 2.98 405.2 T 234 3.35 405.2 T 235 3.42 405.2 T 236 3.18 430.2 T 237 3.75 430.2 T 238 3.43 431.2 T 239 3.32 430.2 T 240 3.59 430.2 T 241 2.93 430.2 T 242 3.78 415.2 T 243 3.76 415.2 T 244 3.90 502.2 T 245 3.12 489.3 T 246 3.24 484.3 T 247 4.36 474.2 T 248 3.26 473.3 T 249 3.56 471.2 T 250 3.59 471.2 T 251 3.52 471.3 T 252 3.21 470.3 T 253 3.09 456.2 T 254 3.47 458.2 T 255 3.14 458.2 T 256 3.96 459.2 T 257 3.96 459.2 T 258 3.64 461.2 T 259 3.41 469.2 T 260 3.36 470.2 T 261 3.61 442.2 T 262 3.21 442.2 T 263 3.07 444.2 T 264 3.55 447.2 T 265 3.00 448.1 T 266 3.94 432.2 T 267 3.28 442.2 T 268 3.00 442.2 T 269 3.88 442.2 T 270 3.50 442.2 T 271 3.36 442.2 T 272 3.44 381.2 T 273 3.85 370.2 T 274 1.49 376.2 Q 275 1.7 439 A 276 1.28 413.2 R 277 1.34 404.2 J 278 2.56 404.1 B 279 1.62 409.2 B 280 3.89 472.2 T 281 3.09 419.2 T 282 3.36 384.2 T 283 3.43 400.2 T 284 3.39 386.2 T 285 1.71 404.1 B 286 0.92 407.1 R 287 1.42 407.2 R 288 1.02 426.1 R 289 1.78 421.2 R 290 1.15 427.3 C 291 0.9 404.2 R 292 1.6 409.1 B 293 0.98 421.2 R 294 3.91 464.3 T 295 4.04 498.3 T 296 4.15 450.3 T 297 3.58 408.2 T 298 3.94 450.3 T 299 3.59 408.2 T 300 3.43 422.2 T 301 3.43 422.2 T 302 3.77 430.2 T 303 3.22 491.3 T 304 3.35 491.3 T 305 3.82 475.2 T 306 4.03 521.3 T 307 3.04 463.2 T 308 3.88 450.3 T 309 3.14 444.2 T 310 3.83 444.2 T 311 3.19 444.2 T 312 3.88 448.2 T 313 3.34 431.2 T 314 3.47 436.3 T 315 3.39 444.2 T 316 3.62 430.2 T 317 3.00 430.2 T 318 4.53 423.2 T 319 4.13 436.3 T 320 3.19 431.2 T 321 3.42 431.2 1 322 3.92 436.3 T 323 3.76 422.2 T 324 3.49 422.2 T 325 3.67 422.2 T 326 3.73 422.2 T 327 3.94 421.2 T 328 4.41 421.1 T 329 3.15 408.2 T 330 3.29 408.2 T 331 3.39 395.2 T 332 3.41 420.2 T 333 3.65 420.2 T 334 3.57 409.2 T 335 3.35 408.2 T 336 3.23 381.2 T 337 3.39 381.2 T 338 2.63 380.2 T 339 1.12 488.3 F 340 3.12 431.2 T 341 3.49 305.2 T 343 0.99 501.3 C 344 1.4 501.3 C 345 1.02 446.3 C 346 1.42 503.4 F 347 2.51 409.2 B 348 1.37 381 I 350 2.11 401.2 F 351 1.16 403.3 F 352 0.94 406.3 F 353 1.87 421.3 F 354 1.11 462.3 F 355 1.14 410.2 F 356 1.37 440.4 C 357 1.99 430.3 F 358 1.24 466 C 359 0.76 412.2 O 360 2.85 401.2 B 361 2.38 400.2 O 362 2.02 489.4 F 363 1.03 487.3 F 364 2.24 381.2 F 365 1.06 423.3 F 366 1.06 423.3 F 367 2 391.2 K 368 1.29 419 I 369 1.35 460.2 O 370 0.74 408.3 S 371 1.76 423.2 O 372 1.2 517.4 F 373 1.75 382.2 O 375 1.23 415.3 F 376 1.78 403.3 F 377 2.03 383.3 O 378 1.78 420.1 K 379 1.64 419 I 381 2.43 421.2 K 382 0.9 411.2 O 383 1.48 386.0 S 384 4.65 409.2 U 385 4.76 409.2 U 387 1.3 415.2 K 388 2.68 502.4 C 389 1.24 405.3 C 392 1.42 414.2 F 393 1.68 417.3 F 394 1.01 421.1 C 395 1.09 400.2 F 396 1.3 449.3 F 397 1.85 399.3 F 398 1.44 460.2 O 399 1.19 428 F 400 1.76 411 I 401 1.41 401 I 402 1.71 386.3 P 403 1.15 508 I 404 1.16 426 I 405 1.25 488 I 406 1.65 402.2 K 407 1.6 407 I 408 1.27 375 I 409 1.39 405 I 410 1.15 414 I 411 2.19 390 I 413 1.26 371.2 I 414 1.3 371.2 I 415 1.2.5 396.2 F 416 1.58 372.2 F 417 1.33 400.1 I 418 1.43 391.1 I 419 1.24 401.1 I

It is understood that the person skilled in the art will be able to prepare the compounds of the present invention using methods known in the art along with the general method of synthesis described herein.

Assay 1: Biochemical Inhibition Assay

NAMPT Protein Purification.

Recombinant His-tagged NAMPT was produced in E. coli cells, purified over a Ni column, and further purified over a size-exclusion column by XTAL Biostructures.

The NAMPT Enzymatic Reaction.

The NAMPT enzymatic reactions were carried out in Buffer A (50 mM Hepes pH 7.5, 50 mM NaCl, 5 mM MgCl₂, and 1 mM THP) in 96-well V-bottom plates. The compound titrations were performed in a separate dilution plate by serially diluting the compounds in DMSO to make a 100× stock. Buffer A (89 μL) containing 33 nM of NAMPT protein was added to 1 μL of 100× compound plate containing controls (e.g. DMSO or blank). The compound and enzyme mixture was incubated for 15 min at room temperature, then 10 μL of 10× substrate and co-factors in Buffer A were added to the test well to make a final concentration of 1 μM NAM, 100 μM 5-Phospho-D-ribose 1-diphosphate (PRPP), and 2.5 mM Adenosine 5′-triphosphate (ATP). The reaction was allowed to proceed for 30 min at room temperature, then was quenched with the addition of 11 μL of a solution of formic acid and L-Cystathionine to make a final concentration of 1% formic acid and 10 μM L-Cystathionine Background and signal strength was determined by addition (or non-addition) of a serial dilution of NMN to a pre-quenched enzyme and cofactor mix.

Quantification of NMN.

A mass spectrometry-based assay was used to measure the NAMPT reaction product, β-nicotinamide mononucleotide (NMN), and the internal control (L-Cystathionine) NMN and L-Cystathionine were detected using the services of Biocius Lifesciences with the RapidFire system. In short, the NMN and L-Cystathionine were bound to a graphitic carbon cartridge in 0.1% formic acid, eluted in 30% acetonitrile buffer, and injected into a Sciex 4000 mass spectrometer. The components of the sample were ionized with electrospray ionization and the positive ions were detected. The Q1 (parent ion) and Q3 (fragment ion) masses of NMN were 334.2 and 123.2, respectively. The Q1 and Q3 for L-Cystathionine were 223.1 and 134.1, respectively. The fragments are quantified and the analyzed by the following method.

Determination of IC₅₀ Values.

First, the NMN signal was normalized to the L-Cystathionine signal by dividing the NMN signal by the L-Cystathionine signal for each well. The signal from the background wells were averaged and subtracted from the test plates. The compound treated cells were then assayed for percent inhibition by using this formula:

% Inh=100−100*x/y

wherein x denotes the average signal of the compound treated wells and y denotes the average signal of the DMSO treated wells.

IC₅₀ values were then determined using the following formula:

IC₅₀=10̂(LOG₁₀(X)+(((50−% Inh at Cmpd Concentration 1)/(XX−YY)*(LOG₁₀(X)−LOG₁₀(Y))))

wherein X denotes the compound concentration 1, Y denotes the compound concentration 2, XX denotes the % inhibition at compound concentration 1 (X), and YY denotes the % inhibition at compound concentration 2 (Y).

The compounds of this invention have IC₅₀ values that are preferably under 1 μM, more preferably under 0.1 μM, and most preferably under 0.01 μM. Results for the compounds tested in this assay are provided in Table 2 below.

Assay 2: In-Vitro Cell Proliferation Assay

Assay Method.

A2780 cells were seeded in 96-well plates at 1×10³ cells/well in 180 μL of culture medium (10% FBS, 1% Pen/Strep Amphotecricin B, RPMI-1640) with and without the addition of either NMN or nicotinamide (NAM). After overnight incubation at 37° C. and 5% CO₂, the compound titrations were performed in a separate dilution plate by serially diluting the compounds in DMSO to make a 1000× stock. The compounds were then further diluted to 10× final concentration in culture media, whereupon 20 μL of each dilution was added to the plated cells with controls (e.g. DMSO and blank) to make a final volume of 200 μL. The final DMSO concentration in each well was 0.1%. The plates were then incubated for 72 hours at 37° C. in a 5% CO₂ incubator. The number of viable cells was then assessed using sulforhodamine B (SRB) assay. Cells were fixed at 4° C. for 1 hour with the addition of 50 μL 30% trichloroacetic acid (TCA) to make a final concentration of 6% TCA. The plates were washed four times with H₂O and allowed to dry for at least 1 hour, whereupon 100 μL of a 4% SRB in 1% acetic acid solution was added to each well and incubated at room temperature for at least 30 min. The plates were then washed three times with 1% acetic acid, dried, and treated with 100 μL of 10 mM Tris-Base solution. The plates were then read in a microplate reader at an absorbance of 570 nm. Background was generated on a separate plate with media only.

Determination of IC₅₀ Values.

First, the signals from the background plate were averaged, then the background was subtracted from the test plates. The compound-treated cells were then assayed for % inhibition by using the following formula:

% Inh=100−100*x/y

wherein x denotes the average signal of the compound-treated cells and y denotes the average signal of the DMSO-treated cells.

IC₅₀ values were then determined using the following formula:

IC₅₀=10̂(LOG₁₀(X)+(((50−% Inh at Cmpd Concentration 1)/(XX−YY)*(LOG₁₀(X)−LOG₁₀(Y))))

wherein X denotes the compound concentration 1, Y denotes the compound concentration 2, XX denotes the % inhibition at compound concentration 1 (X), and YY denotes the % inhibition at compound concentration 2 (Y).

Specificity of Cytotoxicity.

Inhibition of NAMPT could be reversed by the addition of NAM or NMN. The specificity of the compounds were determined via cell viability assay in the presence of the compound and either NAM or NMN. Percent inhibitions were determined using the method given above.

The compounds of this invention have IC₅₀ values that are preferably under more preferably under 0.1 W, and most preferably under 0.01 μM. Most preferable compounds of this invention are compounds that have IC₅₀ values in the enzymatic assay and the cell proliferation assay that are both under 1 μM, more preferably both of the values are under 0.1 μIA, and most preferably both of the values are under 0.01 μM. Results for the compounds tested in this assay are provided in Table 2 (NT=not tested).

TABLE 2 Biochemical and Cell Proliferation Assay Results. Biochemical Cell Proliferation Ex. (IC₅₀) [uM] (IC₅₀) [uM] 1 0.00432 0.000775 2 0.00719 0.202 3 0.00896 0.0697 4 0.00953 0.0489 5 0.0183 0.119 6 0.0454 0.00533 7 0.0648 0.0962 8 0.0735 0.208 9 0.108 0.221 10 0.208 0.791 11 0.255 2.000 12 0.398 2.000 13 0.423 2.000 14 0.988 2.000 15 2.000 NT 16 2.000 2.000 17 2.000 2.000 18 NT NT 19 NT NT 20 0.39832 2.000 21 0.175 2.000 22 0.0175 0.119 23 0.0100 0.0325 24 0.0511 0.00829 25 0.0068 0.0013 26 0.304 2.0 27 0.0504 0.842 28 0.0642 0.616 29 0.0111 0.00303 30 0.416 0.614 31 0.0373 0.0121 32 0.153 2.0 33 1.12 2.0 34 0.0542 0.379 35 0.563 2.0 36 0.0893 0.185 37 0.155 0.643 38 0.040 0.0188 39 0.047 0.232 40 0.13 0.0243 41 0.0143 0.0861 42 0.143 2.0 43 0.279 2.0 44 0.0199 0.0289 45 0.00623 0.00158 46 0.12 0.402 47 0.00459 0.0126 48 0.00996 0.000995 49 0.0479 0.0335 50 0.309 2.0 51 0.173 0.367 52 0.135 0.674 53 0.42 0.846 54 2.0 2.0 55 1.06 2.0 56 0.575 2.0 57 0.223 1.6 58 0.422 2.0 59 0.782 2.0 60 0.309 1.53 61 0.768 2.0 62 0.395 2.0 63 0.177 1.39 64 0.398 2.0 65 0.526 0.931 66 1.04 2.0 67 0.21 0.193 68 0.812 0.414 69 0.386 0.194 70 0.0681 0.492 71 0.0641 0.0137 72 0.0338 0.0481 73 0.0574 0.0258 74 0.231 0.169 75 0.109 0.0809 76 0.214 0.228 77 0.169 1.15 78 0.296 2.0 79 0.755 2.0 80 0.244 1.34 81 0.626 2.0 82 0.398 0.71 83 0.211 1.08 84 0.0767 0.185 85 0.0388 0.0142 86 0.030 0.00453 87 0.802 2.0 88 0.022 0.00977 89 0.228 0.116 90 0.149 0.183 91 0.474 2.0 92 0.189 0.152 93 0.475 0.878 94 0.0706 0.437 95 0.426 2.0 96 0.153 0.711 97 0.421 2.0 98 0.504 2.0 99 0.826 2.0 100 0.462 2.0 101 0.625 2.0 102 1.21 2.0 103 0.44 2.0 104 2.92 2.0 105 0.246 0.755 106 0.396 0.743 107 0.372 2.0 108 0.216 0.449 109 0.0993 0.299 110 0.861 2.0 111 0.579 2.0 112 0.417 2.0 113 0.877 2.0 114 0.325 2.0 115 0.0499 0.0376 116 0.365 0.37 117 0.422 0.752 118 0.449 1.07 119 0.188 0.446 120 0.207 0.0928 121 0.308 1.09 122 0.0974 2.0 123 0.0661 0.083 124 0.151 0.124 125 0.0955 0.221 126 0.273 0.833 127 0.269 2.0 128 0.0914 0.0292 129 0.10 0.0373 130 2.0 2.0 131 0.356 0.326 132 0.0432 0.0072 133 0.194 0.696 134 0.0477 0.514 135 0.0509 0.0364 136 0.104 0.169 137 0.252 0.116 138 0.0941 2.0 139 0.163 2.0 140 0.78 2.0 141 0.222 2.0 142 0.116 0.0971 143 1.22 2.0 144 0.116 0.375 145 0.494 2.0 146 0.0801 0.0745 147 0.0553 0.0744 148 0.288 0.102 149 0.768 0.496 150 0.31 0.265 151 0.0148 0.00423 152 0.0601 0.262 153 0.686 2.0 154 0.208 2.61 155 0.261 2.0 156 NT NT 157 0.0752 2.0 158 0.41 2.0 159 0.0332 0.274 160 0.951 2.0 161 0.123 2.0 162 0.441 2.0 163 0.559 2.0 164 0.118 1.54 165 0.309 2.0 166 0.406 2.0 167 0.314 2.0 168 0.113 2.0 169 0.0558 0.0278 170 0.161 2.0 171 0.0604 2.0 172 0.422 2.0 173 0.146 2.0 174 0.238 0.197 175 0.0467 0.0111 176 0.0376 0.0341 177 0.0363 0.0344 178 0.0257 0.0323 179 0.034 0.0254 180 2.0 2.46 181 0.0173 0.00331 182 0.255 2.0 183 0.314 2.0 184 0.422 2.0 185 0.502 2.0 186 0.0972 0.732 187 0.0446 2.46 188 0.0301 0.0453 189 0.0128 0.00438 190 0.0312 0.0507 191 0.156 1.04 192 0.0239 0.0294 193 0.212 2.0 194 0.668 2.0 195 0.0785 0.218 196 0.0144 0.00367 197 0.0111 0.00961 198 0.131 0.0618 199 0.0144 0.184 200 0.00456 0.0247 201 0.0173 0.0279 202 0.012 0.0282 203 0.544 2.0 204 0.00636 0.00336 205 0.108 0.13 206 0.263 2.0 207 0.0491 0.136 208 0.0347 0.0261 209 0.0803 0.203 210 0.0588 0.316 211 0.0278 0.131 212 0.0528 0.0207 213 0.0318 0.00578 214 0.936 2.0 215 0.0751 0.0658 216 0.179 1.34 218 0.00997 0.00159 219 0.0151 0.00531 220 0.0034 0.00622 221 0.0178 0.0254 222 0.0504 0.0117 223 0.027 0.00192 228 0.0222 0.00474 229 0.0548 0.0184 230 0.0185 0.0299 231 0.201 0.516 232 0.0983 0.207 233 0.0458 0.288 234 0.161 0.164 235 0.288 1.56 236 0.0339 0.0473 237 0.0501 0.166 238 0.0317 0.91 239 0.0329 0.0297 240 0.0263 0.0187 241 0.0273 0.0702 242 0.134 0.713 243 0.0736 0.434 244 0.0264 0.0261 245 0.0525 0.0126 246 0.0211 0.0138 247 0.205 2.0 248 0.0221 0.00439 249 0.254 0.935 250 0.549 2.0 251 0.0776 0.215 252 0.0695 0.344 253 0.0417 0.0554 254 0.0191 0.013 255 0.0499 0.179 256 0.147 0.596 257 0.313 2.0 258 0.0314 0.0203 259 0.161 1.2 260 0.916 2.0 261 0.0245 0.0158 262 0.0695 0.0795 263 0.0265 0.0254 264 0.0683 0.245 265 2.23 2.0 266 0.127 1.47 267 0.321 2.0 268 0.0691 0.0719 269 0.0277 0.016 270 0.0192 0.0192 271 0.0964 0.139 272 0.335 2.0 273 0.0178 0.207 274 0.384 2.0 275 0.121 0.0177 276 0.0391 0.0132 277 0.445 0.755 278 0.479 2.0 279 0.0934 0.00745 280 0.0152 0.00683 281 0.056 0.0185 282 2.0 2.0 283 0.362 0.362 284 0.106 0.105 285 2.0 2.0 286 0.027 0.027 287 0.0245 0.0245 288 0.0606 0.0606 289 0.00999 0.00999 290 0.00454 0.00454 291 0.722 0.722 292 0.693 0.693 293 0.0593 0.0593 294 0.0486 0.0121 295 0.0145 0.000944 296 0.0871 0.0108 297 0.0925 0.278 298 0.213 0.103 299 0.165 0.249 300 1.13 0.335 301 0.0425 0.00421 302 0.0648 0.0903 303 0.478 2.0 304 0.0313 0.0329 305 0.0979 0.0612 306 0.0678 0.0388 307 0.0858 0.0267 308 0.116 2.0 309 0.0822 0.0247 310 0.119 0.0308 311 0.0158 0.0121 312 0.368 0.00961 313 0.0363 0.0159 314 0.0459 0.00676 315 0.0572 0.104 316 0.744 2.0 317 0.0443 0.0152 318 0.436 2.0 319 0.0776 0.055 320 0.13 0.549 321 0.523 2.0 322 0.0282 0.0151 323 0.613 2.0 324 0.137 0.109 325 0.0698 0.0247 326 0.0339 0.0109 327 0.159 0.0776 328 0.040 0.0834 329 0.050 0.0551 330 0.0806 0.159 331 0.0243 0.00704 332 0.0169 0.0338 333 0.297 0.00681 334 0.0599 0.0565 335 0.32 0.59 336 0.0378 0.0635 337 0.0275 0.0231 338 0.169 2.0 339 0.0138 0.0019 340 0.0663 0.429 341 0.162 0.717 343 0.0541 0.0425 344 0.0973 0.072 345 0.14 0.0808 346 0.0103 0.00601 347 0.0113 0.00393 348 0.102 0.0426 350 0.0273 0.00396 351 0.0288 0.00356 352 0.0267 0.00651 353 0.0238 0.00755 354 0.0288 0.00707 355 0.00441 0.00132 356 0.0060 0.00762 357 0.0236 0.0106 358 0.0202 0.00919 359 0.0208 0.0217 360 0.0957 0.0509 361 0.0357 0.0561 362 0.00969 0.0019 363 0.0505 0.0114 364 0.365 0.11 365 0.0845 0.0463 366 0.00993 0.00295 367 0.0183 0.00211 368 0.17 0.991 369 0.167 0.0933 370 0.169 0.115 371 0.0286 0.0302 372 0.0227 0.0275 373 0.0152 0.00703 375 0.00888 0.00111 376 0.0675 0.0161 377 0.0149 0.00159 378 0.241 2.0 379 1.47 2.0 381 0.0233 0.0554 382 0.0229 0.0248 383 0.0158 2.0 384 0.928 0.436 385 0.0824 0.0171 387 0.724 0.535 388 0.034 0.00126 389 0.0216 0.000575 392 0.699 2.0 393 0.0495 0.0185 394 0.0205 0.0145 395 0.193 0.0243 396 0.028 0.0175 397 0.412 0.888 398 0.0125 0.000722 399 0.00331 0.000381 400 0.136 0.222 401 0.29 2.0 402 0.557 2.0 403 0.011 0.0029 404 0.0136 0.00375 405 0.00637 0.00534 406 0.29 2 407 0.0131 0.0726 408 0.00376 0.00101 409 0.0119 0.00103 410 0.0121 0.00393 411 0.121 2.0 413 0.0053 0.00292 414 0.34 0.0535 415 0.0128 0.0142 416 0.082 0.461 417 0.0506 0.83 418 0.0056 0.00352 419 0.00149 0.000489

While the present invention has been described in conjunction with the specific embodiments set forth above, many alternatives, modifications and other variations thereof will be apparent to those of ordinary skill in the art. All such alternatives, modifications and variations are intended to fall within the spirit and scope of the present invention. 

1. A compound of Formula I:

wherein: R is (a) an 8-, 9-, or 10-membered bicyclic heteroaryl comprising one heteroatom selected from N, S, and O, and one, two, or three additional N atoms, wherein said bicyclic heteroaryl is unsubstituted or is substituted with one or more substituents selected from the group consisting of deuterium, amino, alkylamino, dialkylamino, alkyl, halo, cyano, haloalkyl, hydroxy, hydroxyalkyl, and alkoxy, and wherein one or more N atoms of said bicyclic heteroaryl is optionally an N-oxide; or (b) a five- or six-membered nitrogen-linked heterocycloalkyl ring fused to a phenyl or monocyclic five- or six-membered heteroaryl, wherein said phenyl or heteroaryl is unsubstituted or is substituted with one or more substituents selected from the group consisting of deuterium, amino, alkylamino, dialkylamino, alkyl, halo, cyano, haloalkyl, hydroxy, hydroxyalkyl, and alkoxy; and R¹ is H, —(C₁₋₄alkylene)₀₋₁C(O)R^(a), —(C₁₋₄alkylene)₀₋₁CO₂R^(a), —(C₁₋₄alkylene)₀₋₁S(O)R^(a), —(C₁₋₄alkylene)₀₋₁SO₂R^(a), —C(O)NH(R^(a)), —C(O)N(R^(a))₂, or —C(O)C(O)NH(R^(a)); wherein each R^(a) is independently (1) alkyl, unsubstituted or substituted with one or more R^(m) substituents, wherein each R^(m) is independently selected from the group consisting of deuterium, hydroxy, —NR^(b)R^(c), alkoxy, cyano, halo, —C(O)alkyl, —CO₂alkyl, —CONR^(b)R^(c), —S(O)alkyl, —SO₂alkyl, —SO₂NR^(b)R^(c), aryl, heteroaryl, cycloalkyl, heterocycloalkyl, phenoxy, and —O-alkyl-OH; wherein R^(b) is H or alkyl; R^(c) is H, alkyl, alkoxyalkyl, haloalkyl, —C(O)alkyl, —CO₂alkyl, —SO₂alkyl, —C(O)NH₂, or C(O)H; and each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl group within R^(m) is unsubstituted or substituted with one or more substituents independently selected from the group consisting of alkyl, haloalkyl, hydroxy, —NR^(b)R^(c), alkoxy, haloalkoxy, cyano, halo, oxo, —C(O)alkyl, —CO₂alkyl, —C(O)-heterocycloalkyl, —CONR^(b)R^(c), —S(O)alkyl, —SO₂alkyl, —SO₂-haloalkyl, —SO₂NR^(b)R^(c), aryl, heteroaryl, cycloalkyl, and heterocycloalkyl; or two substituents taken together form a fused heteroaryl, cycloalkyl, or heterocycloalkyl ring; wherein each alkyl or alkoxy is unsubstituted or substituted with phenyl, —NR^(b)R^(c), heterocycloalkyl, heteroaryl, or —C(O)alkyl; and each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl is unsubstituted or substituted with alkyl, halo, or C(O)alkyl, (2) phenyl, cycloalkyl, heteroaryl, or heterocycloalkyl, each unsubstituted or substituted with one or more R^(g) substituents; wherein each R^(g) is independently selected from the group consisting of alkyl, haloalkyl, hydroxy, —NR^(b)R^(c), alkoxy, haloalkoxy, cyano, halo, oxo, —C(O)alkyl, —CO₂alkyl, —C(O)-heterocycloalkyl, —CONR^(b)R^(c), —S(O)alkyl, —SO₂alkyl, —SO₂-haloalkyl, —SO₂NR^(b)R^(c), aryl, heteroaryl, cycloalkyl, and heterocycloalkyl; or two R^(g) substituents taken together form a fused phenyl, heteroaryl, cycloalkyl, or heterocycloalkyl ring; wherein each alkyl or alkoxy is unsubstituted or substituted with —NR^(b)R^(c), heterocycloalkyl, heteroaryl, or —C(O)alkyl; and each aryl, heteroaryl, cycloalkyl, and heterocycloalkyl is unsubstituted or substituted with alkyl, halo, —CO₂alkyl, or —C(O)alkyl; or (3) —NR^(x)R^(y), where R^(x) is H or alkyl; and R^(y) is H, alkyl, alkoxyalkyl, haloalkyl, —C(O)alkyl, —CO₂alkyl, or —SO₂alkyl; R² and R³ are each independently H or deuterium; and n is 1 or 2; or a stereoisomer thereof, or a pharmaceutically acceptable salt of such a compound or stereoisomer.
 2. The compound of claim 1, wherein R is an 8- or 9-membered heteroaryl, unsubstituted or substituted as described for claim
 1. 3. The compound of claim 1, wherein R is:

each unsubstituted or substituted as described for claim
 1. 4. The compound of claim 1, wherein, R is a five- or six-membered nitrogen-linked heterocycloalkyl ring fused to an unsubstituted or substituted phenyl or monocyclic heteroaryl, as defined in claim
 1. 5. The compound of claim 1, wherein R is


6. The compound of claim 1, wherein R¹ is H.
 7. The compound of claim 1, wherein R¹ is —C(O)R^(a), —CO₂R^(a), —S(O)R^(a), or —SO₂R^(a).
 8. The compound of claim 1, wherein R^(a) is alkyl, unsubstituted or substituted as described for claim
 1. 9. The compound of claim 1, wherein R^(a) is methyl, ethyl, propyl, isopropyl, tert-butyl, isobutyl, isopentyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, pyrrolyl, furanyl, thiophenyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, triazoyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, isoindolinyl, azetidinyl, oxetanyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, or tetrahydrothiophenyl, each unsubstituted or substituted.
 10. The compound of claim 1, wherein R^(a) is phenyl, cycloalkyl, heteroaryl, or heterocycloalkyl, each unsubstituted or substituted with one or more substituents selected from the group consisting of fluoro, oxo, methyl, —CONH₂, acetyl, —SO₂methyl, —C(O)-isopropyl, pyridazinyl, triazolyl, dimethylaminomethyl, cyano, methyl-triazolyl-methoxy, trifluoromethoxy, pyrrolidinylmethyl, acetylamino, tetrazolylmethyl, methyl-tetrazolyl-methyl, methyl-imidazolyl-methyl, —NHSO₂methyl, 1,1-dioxothiomorpholinyl, 4-methyl-piperazinylmethyl, —NHCONH₂, —SO₂CF₃, morpholinylmethyl, imidazolyl, —SO₂NH₂, methylpiperidinyl, methyl-piperazinyl, —C(O)(4-methyl-piperazinyl), morpholinyl, trifluoromethyl, cyclopropyl, ethyl, isoxazolyl, tetrazolyl, isopropyl, phenyl, fluoro-phenyl, tert-butyl, benzyl, N-methylpyrrolidinyl, N-acetyl-pyrrolidinyl, isobutyl, propyl, methylpyrazolyl, trifluoroethyl, pyrimidinyl, oxo, acetyl, cyano, —CO₂-tert-butyl, and amino.
 11. The compound of claim 1, wherein R^(a) is alkyl, unsubstituted or substituted with one or more substituents selected from the group consisting of fluoro, tert-butoxy, —C(O)NMe₂, —NHCHO, methoxy, phenoxy, cyano, acetyl, hydroxy, —OCH₂C(CH₃)═OH, —NH(acetyl), and —N(Me)(acetyl).
 12. The compound of claim 1, wherein R¹ is —SO₂R^(a), where R^(a) is methyl, ethyl, phenyl, benzyl, or 2,2-dimethylpropyl.
 13. The compound of claim 1, wherein R¹ is —C(O)NHR^(a), wherein R^(a) is methyl, ethyl, propyl, isopropyl, tertobutyl, cyclohexyl, —CH₂-cyclohexyl, oxetanyl, or methyloxetanyl, or R^(a) is a phenyl or benzyl group, each optionally substituted with one or more substituents selected from the group consisting of cyano, methyl, fluoro, methoxy, and chloro.
 14. The compound of claim 1, wherein both R² and R³ are H.
 15. The compound of claim 1, which is a compound of Formula I-a:

wherein R, R¹, R², and R³ are as defined for Formula I; or a stereoisomer thereof, or a pharmaceutically acceptable salt of such a compound or stereoisomer.
 16. A compound selected from the group consisting of:

and stereoisomers thereof, and pharmaceutically acceptable salts of such compounds and stereoisomers.
 17. A pharmaceutical composition comprising: (a) an effective amount of at least one compound of claim 1; and (b) a pharmaceutically acceptable carrier.
 18. The pharmaceutical composition of claim 17, further comprising therapeutically effective amounts of one or more additional adjunctive active agents.
 19. The pharmaceutical composition of claim 18, wherein said one or more additional adjunctive active agents are selected from the group consisting of cytotoxic agent, cisplatin, doxorubicin, taxotere, taxol, etoposide, irinotecan, camptostar, topotecan, paclitaxel, docetaxel, the epothilones, tamoxifen, 5-fluorouracil, methoxtrexate, temozolomide, cyclophosphamide, SCH 66336, tipifarnib (Zarnestra®), R115777, L778,123, BMS 214662, Iressa®, Tarceva®, C225, GLEEVEC®, Intron®, Peg-Intron®, aromatase combinations, ara-C, adriamycin, cytoxan, gemcitabine, Uracil mustard, Chlormethine, Ifosfamide, Melphalan, Chlorambucil, Pipobroman, Triethylenemelamine, Triethylenethiophosphoramine, Busulfan, Carmustine, Lomustine, Streptozocin, Dacarbazine, Floxuridine, Cytarabine, 6-Mercaptopurine, 6-Thioguanine, Fludarabine phosphate, oxaliplatin, leucovirin, oxaliplatin (ELOXATIN®), Pentostatine, Vinblastine, Vincristine, Vindesine, Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Mithramycin™, Deoxycoformycin, Mitomycin-C, L-Asparaginase, Teniposide 17α-Ethinylestradiol, Diethylstilbestrol, Testosterone, Prednisone, Fluoxymesterone, Dromostanolone propionate, Testolactone, Megestrol acetate, Methylprednisolone, Methyltestosterone, Prednisolone, Triamcinolone, Chlorotrianisene, Hydroxyprogesterone, Aminoglutethimide, Estramustine, Medroxyprogesteroneacetate, Leuprolide, Flutamide, Toremifene, goserelin, Carboplatin, Hydroxyurea, Amsacrine, Procarbazine, Mitotane, Mitoxantrone, Levamisole, Navelbene, Anastrazole, Letrazole, Capecitabine, Reloxafine, Droloxafine, Hexamethylmelamine, Avastin, herceptin, Bexxar, Velcade, Zevalin, Trisenox, Xeloda, Vinorelbine, Porfimer, Erbitux, Liposomal, Thiotepa, Altretamine, Melphalan, Trastuzumab, Lerozole, Fulvestrant, Exemestane, Ifosfomide, Rituximab, C225, Campath, leucovorin, and dexamethasone, bicalutamide, carboplatin, chlorambucil, cisplatin, letrozole, megestrol, valrubicin, vinblastine and NIASPAN®.
 20. The pharmaceutical composition of claim 17 further comprising a rescuing agent.
 21. The pharmaceutical composition of claim 20, wherein the rescuing agent is selected from the group consisting of nicotinamide, nicotinic acid, and nicotinamide mononucleotide (NMN).
 22. A method of treating a subject suffering from or diagnosed with a disease or medical condition mediated by NAMPT activity, comprising administering to the subject in need of such treatment an effective amount of at least one compound of claim
 1. 23. The method of claim 22, wherein the disease or medical condition is a solid or liquid tumor, non-small cell lung cancer, leukemia, lymphoma, ovarian cancer, glioma, breast cancer, uterine cancer, colon cancer, cervical cancer, lung cancer, prostate cancer, skin cancer, rhino-gastric tumors, colorectal cancer, CNS cancer, bladder cancer, pancreatic cancer, Hodgkin's disease, rheumatoid arthritis, diabetes, atherosclerosis, sepsis, aging or inflammation.
 24. The method of claim 22, further comprising administering to the subject an effective amount of at least one compound selected from the group consisting of: a cytotoxic agent, cisplatin, doxorubicin, taxotere, taxol, etoposide, irinotecan, camptostar, topotecan, paclitaxel, docetaxel, the epothilones, tamoxifen, 5-fluorouracil, methoxtrexate, temozolomide, cyclophosphamide, SCH 66336, tipifarnib (Zarnestra®), R115777, L778,123, BMS 214662, Iressa®, Tarceva®, C225, GLEEVEC®, Intron®, Peg-Intron®, aromatase combinations, ara-C, adriamycin, cytoxan, gemcitabine, Uracil mustard, Chlormethine, Ifosfamide, Melphalan, Chlorambucil, Pipobroman, Triethylenemelamine, Triethylenethiophosphoramine, Busulfan, Carmustine, Lomustine, Streptozocin, Dacarbazine, Floxuridine, Cytarabine, 6-Mercaptopurine, 6-Thioguanine, Fludarabine phosphate, leucovirin, oxaliplatin (ELOXATIN®), Pentostatine, vincristine, Vindesine, Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Mithramycin™, Deoxycoformycin, Mitomycin-C, L-Asparaginase, Teniposide 17α-Ethinylestradiol, Diethylstilbestrol, Testosterone, Prednisone, Fluoxymesterone, Dromostanolone propionate, Testolactone, Megestrol acetate, Methylprednisolone, Methyltestosterone, Prednisolone, Triamcinolone, Chlorotrianisene, Hydroxyprogesterone, Aminoglutethimide, Estramustine, Medroxyprogesteroneacetate, Leuprolide, Flutamide, Toremifene, goserelin, Carboplatin, Hydroxyurea, Amsacrine, Procarbazine, Mitotane, Mitoxantrone, Levamisole, Navelbene, Anastrazole, Letrazole, Capecitabine, Reloxafine, Droloxafine, Hexamethylmelamine, Avastin, herceptin, Bexxar, Velcade, Zevalin, Trisenox, Xeloda, Vinorelbine, Porfimer, Erbitux, Liposomal, Thiotepa, Altretamine, Melphalan, Trastuzumab, Lerozole, Fulvestrant, Exemestane, Ifosfomide, Rituximab, C225, Campath, leucovorin, dexamethasone, bicalutamide, chlorambucil, letrozole, megestrol, valrubicin, vinblastine, and NIASPAN®.
 25. The method of claim 22 further comprising administering an effective amount of a rescuing agent.
 26. The pharmaceutical composition of claim 25, wherein the rescuing agent is selected from the group consisting of nicotinamide, nicotinic acid, and nicotinamide mononucleotide (NMN). 